Mark Brongersma

All Publications

• Roadmap for Optical Metasurfaces. ACS photonics Kuznetsov, A. I., Brongersma, M. L., Yao, J., Chen, M. K., Levy, U., Tsai, D. P., Zheludev, N. I., Faraon, A., Arbabi, A., Yu, N., Chanda, D., Crozier, K. B., Kildishev, A. V., Wang, H., Yang, J. K., Valentine, J. G., Genevet, P., Fan, J. A., Miller, O. D., Majumdar, A., Fröch, J. E., Brady, D., Heide, F., Veeraraghavan, A., Engheta, N., Alù, A., Polman, A., Atwater, H. A., Thureja, P., Paniagua-Dominguez, R., Ha, S. T., Barreda, A. I., Schuller, J. A., Staude, I., Grinblat, G., Kivshar, Y., Peana, S., Yelin, S. F., Senichev, A., Shalaev, V. M., Saha, S., Boltasseva, A., Rho, J., Oh, D. K., Kim, J., Park, J., Devlin, R., Pala, R. A. 2024; 11 (3): 816-865

  Abstract

  Metasurfaces have recently risen to prominence in optical research, providing unique functionalities that can be used for imaging, beam forming, holography, polarimetry, and many more, while keeping device dimensions small. Despite the fact that a vast range of basic metasurface designs has already been thoroughly studied in the literature, the number of metasurface-related papers is still growing at a rapid pace, as metasurface research is now spreading to adjacent fields, including computational imaging, augmented and virtual reality, automotive, display, biosensing, nonlinear, quantum and topological optics, optical computing, and more. At the same time, the ability of metasurfaces to perform optical functions in much more compact optical systems has triggered strong and constantly growing interest from various industries that greatly benefit from the availability of miniaturized, highly functional, and efficient optical components that can be integrated in optoelectronic systems at low cost. This creates a truly unique opportunity for the field of metasurfaces to make both a scientific and an industrial impact. The goal of this Roadmap is to mark this "golden age" of metasurface research and define future directions to encourage scientists and engineers to drive research and development in the field of metasurfaces toward both scientific excellence and broad industrial adoption.

  View details for DOI 10.1021/acsphotonics.3c00457

  View details for PubMedID 38550347

  View details for PubMedCentralID PMC10971570

• Direct electron beam patterning of electro-optically active PEDOT:PSS NANOPHOTONICS Doshi, S., Ludescher, D., Karst, J., Floess, M., Carlstrom, J., Li, B., Hemed, N., Duh, Y., Melosh, N. A., Hentschel, M., Brongersma, M., Giessen, H. 2024

  View details for DOI 10.1515/nanoph-2023-0640

  View details for Web of Science ID 001135766900001

• Determining hot-carrier transport dynamics from terahertz emission. Science (New York, N.Y.) Taghinejad, M., Xia, C., Hrton, M., Lee, K. T., Kim, A. S., Li, Q., Guzelturk, B., Kalousek, R., Xu, F., Cai, W., Lindenberg, A. M., Brongersma, M. L. 2023; 382 (6668): 299-305

  Abstract

  Understanding the ultrafast excitation and transport dynamics of plasmon-driven hot carriers is critical to the development of optoelectronics, photochemistry, and solar-energy harvesting. However, the ultrashort time and length scales associated with the behavior of these highly out-of-equilibrium carriers have impaired experimental verification of ab initio quantum theories. Here, we present an approach to studying plasmonic hot-carrier dynamics that analyzes the temporal waveform of coherent terahertz bursts radiated by photo-ejected hot carriers from designer nano-antennas with a broken symmetry. For ballistic carriers ejected from gold antennas, we find an ~11-femtosecond timescale composed of the plasmon lifetime and ballistic transport time. Polarization- and phase-sensitive detection of terahertz fields further grant direct access to their ballistic transport trajectory. Our approach opens explorations of ultrafast carrier dynamics in optically excited nanostructures.

  View details for DOI 10.1126/science.adj5612

  View details for PubMedID 37856614

• Physics-Informed Machine Learning for Inverse Design of Optical Metamaterials ADVANCED PHOTONICS RESEARCH Sarkar, S., Ji, A., Jermain, Z., Lipton, R., Brongersma, M., Dayal, K., Noh, H. 2023

  View details for DOI 10.1002/adpr.202300158

  View details for Web of Science ID 001078969300001

• Off-axis metasurfaces for folded flat optics. Nature communications Born, B., Lee, S. H., Song, J. H., Lee, J. Y., Ko, W., Brongersma, M. L. 2023; 14 (1): 5602

  Abstract

  The overall size of an optical system is limited by the volume of the components and the internal optical path length. To reach the limits of miniaturization, it is possible to reduce both component volume and path length by combining the concepts of metasurface flat optics and folded optics. In addition to their subwavelength component thickness, metasurfaces enable bending conventional folded geometries off axis beyond the law of reflection. However, designing metasurfaces for highly off-axis illumination with visible light in combination with a high numerical aperture is non-trivial. In this case, traditional designs with gradient metasurfaces exhibit low diffraction efficiencies and require the use of deep-subwavelength, high-index, and high-aspect-ratio semiconductor nanostructures that preclude inexpensive, large-area nanofabrication. Here, we describe a design approach that enables the use of low-index (n ≈ 1.5), low-aspect ratio structures for off-axis metagratings that can redirect and focus visible light (λ = 532 nm) with near-unity efficiency. We show that fabricated optical elements offer a very large angle-of-view (110°) and lend themselves to scalable fabrication by nano-imprint lithography.

  View details for DOI 10.1038/s41467-023-41123-x

  View details for PubMedID 37699876

  View details for PubMedCentralID 6180047

• Transfer Matrix Method-Compatible Model for Metamaterial Stacks ACS PHOTONICS Song, J., Lalanne, P., Seo, M., Brongersma, M. L. 2023

  View details for DOI 10.1021/acsphotonics.3c00693

  View details for Web of Science ID 001031276500001

• A Purcell-enabled monolayer semiconductor free-space optical modulator NATURE PHOTONICS Li, Q., Song, J., Xu, F., van de Groep, J., Hong, J., Daus, A., Lee, Y., Johnson, A. C., Pop, E., Liu, F., Brongersma, M. L. 2023

  View details for DOI 10.1038/s41566-023-01250-9

  View details for Web of Science ID 001031418200001

• Ultrafast Wavefront Shaping via Space-Time Refraction ACS PHOTONICS Fan, Q., Shaltout, A. M., van de Groep, J., Brongersma, M. L., Lindenberg, A. M. 2023

  View details for DOI 10.1021/acsphotonics.3c00498

  View details for Web of Science ID 001021440200001

• Controlling Valley-Specific Light Emission from Monolayer MoS2 with Achiral Dielectric Metasurfaces. Nano letters Liu, Y., Lau, S. C., Cheng, W., Johnson, A., Li, Q., Simmerman, E., Karni, O., Hu, J., Liu, F., Brongersma, M. L., Heinz, T. F., Dionne, J. A. 2023

  Abstract

  Excitons in two-dimensional transition metal dichalcogenides have a valley degree of freedom that can be optically manipulated for quantum information processing. Here, we integrate MoS2 monolayers with achiral silicon disk array metasurfaces to enhance and control valley-specific absorption and emission. Through the coupling to the metasurface electric and magnetic Mie modes, the intensity and lifetime of the emission of neutral excitons, trions, and defect bound excitons can be enhanced and shortened, respectively, while the spectral shape can be modified. Additionally, the degree of polarization (DOP) of exciton and trion emission from the valley can be symmetrically enhanced at 100 K. The DOP increase is attributed to both the metasurface-enhanced chiral absorption of light and the metasurface-enhanced exciton emission from the Purcell effect. Combining Si-compatible photonic design with large-scale 2D materials integration, our work makes an important step toward on-chip valleytronic applications approaching room-temperature operation.

  View details for DOI 10.1021/acs.nanolett.3c01630

  View details for PubMedID 37347949

• Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature NANOPHOTONICS van de Groep, J., Li, Q., Song, J., Kik, P. G., Brongersma, M. L. 2023

  View details for DOI 10.1515/nanoph-2023-0193

  View details for Web of Science ID 001015007800001

• Multi-resonant Mie Resonator Arrays for Broadband Light Trapping in Ultrathin c-Si Solar Cells. Advanced materials (Deerfield Beach, Fla.) Lee, N., Xue, M., Hong, J., van de Groep, J., Brongersma, M. L. 2023: e2210941

  Abstract

  Effective photon management is critical to realize high power conversion efficiencies for thin crystalline Si (c-Si) solar cells. Standard few-100-m-thick bulk cells achieve light trapping with macroscopic surface textures covered by thin, continuous antireflection coatings. Such sizeable textures are challenging to implement on ultrathin cells. Here, we illustrate how nanoscale Mie-resonator-arrays with a bi-modal size distribution support multiple resonances that can work in concert to achieve simultaneous antireflection and light-trapping across the broad solar spectrum. We experimentally demonstrate the effectiveness of these light-trapping antireflection coatings (LARCs) on a 2.8-m-thick c-Si solar cell. The measured short-circuit current and corresponding power conversion efficiency are notably improved, achieving efficiencies as high as 11.2%. Measurements of the saturation current density on completed cells indicate that thermal oxides can effectively limit surface recombination. The presented design principles are applicable to a wide range of solar cells. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/adma.202210941

  View details for PubMedID 37129216

• Dynamically Tunable Optical Cavities with Embedded Nematic Liquid Crystalline Networks. Advanced materials (Deerfield Beach, Fla.) Zubritskaya, I., Cichelero, R., Faniayeu, I., Martella, D., Nocentini, S., Rudquist, P., Wiersma, D. S., Brongersma, M. L. 2023: e2209152

  Abstract

  Tunable metal-insulator-metal (MIM) Fabry-Perot cavities that can dynamically control light enable novel sensing, imaging, and display applications. However, the realization of dynamic cavities incorporating stimuli-responsive materials pose a significant engineering challenge. Current approaches rely on refractive index modulation and suffer from low dynamic tunability, high losses, limited spectral ranges and require liquid and hazardous materials for operation. To overcome these challenges, a new tuning mechanism employing reversible mechanical adaptations of a polymer network is proposed and dynamic tuning of optical resonances is demonstrated. Solid-state temperature-responsive optical coatings are developed by preparing a monodomain nematic liquid crystalline network (LCN) and are incorporated between metallic mirrors to form active optical microcavities. LCN microcavities offer large, reversible and highly linear spectral tuning of Fabry-Perot resonances reaching wavelength-shifts up to 40nm via thermo-mechanical actuation while featuring outstanding repeatability and precision over more than 100 heating-cooling cycles. This degree of tunability allows for reversible switching between the reflective and the absorbing states of the device over the entire visible and near-infrared spectral regions, reaching large changes in reflectance with modulation efficiency DeltaR = 79%. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/adma.202209152

  View details for PubMedID 36683324

• Nonlocal metasurface for circularly polarized light detection OPTICA Hong, J., Van De Groep, J., Lee, N., Kim, S., Lalanne, P., Kik, P. G., Brongersma, M. L. 2023; 10 (1): 134-141

  View details for DOI 10.1364/OPTICA.468252

  View details for Web of Science ID 000925594800002

• Quantitative phase contrast imaging with a nonlocal angle-selective metasurface. Nature communications Ji, A., Song, J. H., Li, Q., Xu, F., Tsai, C. T., Tiberio, R. C., Cui, B., Lalanne, P., Kik, P. G., Miller, D. A., Brongersma, M. L. 2022; 13 (1): 7848

  Abstract

  Phase contrast microscopy has played a central role in the development of modern biology, geology, and nanotechnology. It can visualize the structure of translucent objects that remains hidden in regular optical microscopes. The optical layout of a phase contrast microscope is based on a 4 f image processing setup and has essentially remained unchanged since its invention by Zernike in the early 1930s. Here, we propose a conceptually new approach to phase contrast imaging that harnesses the non-local optical response of a guided-mode-resonator metasurface. We highlight its benefits and demonstrate the imaging of various phase objects, including biological cells, polymeric nanostructures, and transparent metasurfaces. Our results showcase that the addition of this non-local metasurface to a conventional microscope enables quantitative phase contrast imaging with a 0.02π phase accuracy. At a high level, this work adds to the growing body of research aimed at the use of metasurfaces for analog optical computing.

  View details for DOI 10.1038/s41467-022-34197-6

  View details for PubMedID 36543788

  View details for PubMedCentralID PMC9772391

• Metasurface optofluidics for dynamic control of light fields. Nature nanotechnology Li, Q., van de Groep, J., White, A. K., Song, J., Longwell, S. A., Fordyce, P. M., Quake, S. R., Kik, P. G., Brongersma, M. L. 2022

  Abstract

  The ability to manipulate light and liquids on integrated optofluidics chips has spurred a myriad of important developments in biology, medicine, chemistry and display technologies. Here we show how the convergence of optofluidics and metasurface optics can lead to conceptually new platforms for the dynamic control of light fields. We first demonstrate metasurface building blocks that display an extreme sensitivity in their scattering properties to their dielectric environment. These blocks are then used to create metasurface-based flat optics inside microfluidic channels where liquids with different refractive indices can be directed to manipulate their optical behaviour. We demonstrate the intensity and spectral tuning of metasurface colour pixels as well as on-demand optical elements. We finally demonstrate automated control in an integrated meta-optofluidic platform to open up new display functions. Combined with large-scale microfluidic integration, our dynamic-metasurface flat-optics platform could open up the possibility of dynamic display, imaging, holography and sensing applications.

  View details for DOI 10.1038/s41565-022-01197-y

  View details for PubMedID 36163507

• Creating the ultimate virtual reality display. Science (New York, N.Y.) Joo, W., Brongersma, M. L. 2022; 377 (6613): 1376-1378

  Abstract

  Scientists are exploring new material designs to make smaller and denser pixel displays.

  View details for DOI 10.1126/science.abq7011

  View details for PubMedID 36137048

• Enhanced Light Emission from Monolayer MoS2 by Doubly Resonant Spherical Si Nanoantennas br ACS PHOTONICS Shinomiya, H., Sugimoto, H., Hinamoto, T., Lee, Y., Brongersma, M. L., Fujii, M. 2022; 9 (5): 1741-1747

  View details for DOI 10.1021/acsphotonics.2c00142

  View details for Web of Science ID 000804570900032

• Excitons in strained and suspended monolayer WSe2 2D MATERIALS Aslan, B., Yule, C., Yu, Y., Lee, Y., Heinz, T. F., Cao, L., Brongersma, M. L. 2022; 9 (1)

  View details for DOI 10.1088/2053-1583/ac2d15

  View details for Web of Science ID 000709982700001

• High-specific-power flexible transition metal dichalcogenide solar cells. Nature communications Nassiri Nazif, K., Daus, A., Hong, J., Lee, N., Vaziri, S., Kumar, A., Nitta, F., Chen, M. E., Kananian, S., Islam, R., Kim, K., Park, J., Poon, A. S., Brongersma, M. L., Pop, E., Saraswat, K. C. 2021; 12 (1): 7034

  Abstract

  Semiconducting transition metal dichalcogenides (TMDs) are promising for flexible high-specific-power photovoltaics due to their ultrahigh optical absorption coefficients, desirable band gaps and self-passivated surfaces. However, challenges such as Fermi-level pinning at the metal contact-TMD interface and the inapplicability of traditional doping schemes have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In addition, fabrication on flexible substrates tends to contaminate or damage TMD interfaces, further reducing performance. Here, we address these fundamental issues by employing: (1) transparent graphene contacts to mitigate Fermi-level pinning, (2) MoOx capping for doping, passivation and anti-reflection, and (3) a clean, non-damaging direct transfer method to realize devices on lightweight flexible polyimide substrates. These lead to record PCE of 5.1% and record specific power of 4.4Wg-1 for flexible TMD (WSe2) solar cells, the latter on par with prevailing thin-film solar technologies cadmium telluride, copper indium gallium selenide, amorphous silicon and III-Vs. We further project that TMD solar cells could achieve specific power up to 46Wg-1, creating unprecedented opportunities in a broad range of industries from aerospace to wearable and implantable electronics.

  View details for DOI 10.1038/s41467-021-27195-7

  View details for PubMedID 34887383

• Photochemistry democratizes 3D nanoprinting NATURE PHOTONICS Braun, P. V., Brongersma, M. L. 2021; 15 (12): 871-873

  View details for DOI 10.1038/s41566-021-00911-x

  View details for Web of Science ID 000723677100006

• Non-local metasurfaces for spectrally decoupled wavefront manipulation and eye tracking. Nature nanotechnology Song, J., van de Groep, J., Kim, S. J., Brongersma, M. L. 2021

  Abstract

  Metasurface-based optical elements typically manipulate light waves by imparting space-variant changes in the amplitude and phase with a dense array of scattering nanostructures. The highly localized and low optical-quality-factor (Q) modes of nanostructures are beneficial for wavefront shaping as they afford quasi-local control over the electromagnetic fields. However, many emerging imaging, sensing, communication, display and nonlinear optics applications instead require flat, high-Q optical elements that provide substantial energy storage and a much higher degree of spectral control over the wavefront. Here, we demonstrate high-Q, non-local metasurfaces with atomically thin metasurface elements that offer notably enhanced light-matter interaction and fully decoupled optical functions at different wavelengths. We illustrate a possible use of such a flat optic in eye tracking for eyewear. Here, a metasurface patterned on a regular pair of eye glasses provides an unperturbed view of the world across the visible spectrum and redirects near-infrared light to a camera to allow imaging of the eye.

  View details for DOI 10.1038/s41565-021-00967-4

  View details for PubMedID 34594006

• Self-Assembled Nano-Lotus Pod Metasurface for Light Trapping ACS PHOTONICS Lee, N., Kim, R., Kim, J., Ko, J., Park, S., Kim, S., Brongersma, M. L., Shin, J. 2021; 8 (6): 1616-1622

  View details for DOI 10.1021/acsphotonics.0c01882

  View details for Web of Science ID 000664306400013

• Plasmon Launching and Scattering by Silicon Nanoparticles ACS PHOTONICS Assadillayev, A., Hinamoto, T., Fujii, M., Sugimoto, H., Brongersma, M. L., Raza, S. 2021; 8 (6): 1582-1591

  View details for DOI 10.1021/acsphotonics.0c01554

  View details for Web of Science ID 000664306400010

• Fundamental Limitations of Huygens' Metasurfaces for Optical Beam Shaping LASER & PHOTONICS REVIEWS Gigli, C., Li, Q., Chavel, P., Leo, G., Brongersma, M. L., Lalanne, P. 2021

  View details for DOI 10.1002/lpor.202000448

  View details for Web of Science ID 000660500800001

• Structural color from a coupled nanowire pair beyond the bonding and antibonding model OPTICA Li, Q., Wu, T., van de Groep, J., Lalanne, P., Brongersma, M. L. 2021; 8 (4): 464-470

  View details for DOI 10.1364/OPTICA.418888

  View details for Web of Science ID 000642200300006

• Electrical tuning of phase-change antennas and metasurfaces. Nature nanotechnology Wang, Y., Landreman, P., Schoen, D., Okabe, K., Marshall, A., Celano, U., Wong, H. P., Park, J., Brongersma, M. L. 2021

  Abstract

  The success of semiconductor electronics is built on the creation of compact, low-power switching elements that offer routing, logic and memory functions. The availability of nanoscale optical switches could have a similarly transformative impact on the development of dynamic and programmable metasurfaces, optical neural networks and quantum information processing. Phase-change materials are uniquely suited to enable their creation as they offer high-speed electrical switching between amorphous and crystalline states with notably different optical properties. Their high refractive index has already been harnessed to fashion them into compact optical antennas. Here, we take the next important step, by showing electrically-switchable phase-change antennas and metasurfaces that offer strong, reversible, non-volatile, multi-phase switching and spectral tuning of light scattering in the visible and near-infrared spectral ranges. Their successful implementation relies on a careful joint thermal and optical optimization of the antenna elements that comprise a silver strip that simultaneously serves as a plasmonic resonator and a miniature heating stage. Our metasurface affords electrical modulation of the reflectance by more than fourfold at 755nm.

  View details for DOI 10.1038/s41565-021-00882-8

  View details for PubMedID 33875869

• High-Performance p-n Junction Transition Metal Dichalcogenide Photovoltaic Cells Enabled by MoOx Doping and Passivation. Nano letters Nassiri Nazif, K., Kumar, A., Hong, J., Lee, N., Islam, R., McClellan, C. J., Karni, O., van de Groep, J., Heinz, T. F., Pop, E., Brongersma, M. L., Saraswat, K. C. 2021

  Abstract

  Layered semiconducting transition metal dichalcogenides (TMDs) are promising materials for high-specific-power photovoltaics due to their excellent optoelectronic properties. However, in practice, contacts to TMDs have poor charge carrier selectivity, while imperfect surfaces cause recombination, leading to a low open-circuit voltage (VOC) and therefore limited power conversion efficiency (PCE) in TMD photovoltaics. Here, we simultaneously address these fundamental issues with a simple MoOx (x 3) surface charge-transfer doping and passivation method, applying it to multilayer tungsten disulfide (WS2) Schottky-junction solar cells with initially near-zero VOC. Doping and passivation turn these into lateral p-n junction photovoltaic cells with a record VOC of 681 mV under AM 1.5G illumination, the highest among all p-n junction TMD solar cells with a practical design. The enhanced VOC also leads to record PCE in ultrathin (<90 nm) WS2 photovoltaics. This easily scalable doping and passivation scheme is expected to enable further advances in TMD electronics and optoelectronics.

  View details for DOI 10.1021/acs.nanolett.1c00015

  View details for PubMedID 33852295

• Atomic-Scale Control of Coherent Thermal Radiation ACS PHOTONICS Zhao, B., Song, J., Brongersma, M., Fan, S. 2021; 8 (3): 872–78

  View details for DOI 10.1021/acsphotonics.0c01879

  View details for Web of Science ID 000630366900025

• Nanoelectromechanical modulation of a strongly-coupled plasmonic dimer. Nature communications Song, J., Raza, S., van de Groep, J., Kang, J., Li, Q., Kik, P. G., Brongersma, M. L. 2021; 12 (1): 48

  Abstract

  The ability of two nearly-touching plasmonic nanoparticles to squeeze light into a nanometer gap has provided a myriad of fundamental insights into light-matter interaction. In this work, we construct a nanoelectromechanical system (NEMS) that capitalizes on the unique, singular behavior that arises at sub-nanometer particle-spacings to create an electro-optical modulator. Using in situ electron energy loss spectroscopy in a transmission electron microscope, we map the spectral and spatial changes in the plasmonic modes as they hybridize and evolve from a weak to a strong coupling regime. In the strongly-coupled regime, we observe a very large mechanical tunability (~250meV/nm) of the bonding-dipole plasmon resonance of the dimer at ~1nm gap spacing, right before detrimental quantum effects set in. We leverage our findings to realize a prototype NEMS light-intensity modulator operating at ~10MHz and with a power consumption of only 4 fJ/bit.

  View details for DOI 10.1038/s41467-020-20273-2

  View details for PubMedID 33397929

• The road to atomically thin metasurface optics NANOPHOTONICS Brongersma, M. L. 2021; 10 (1): 643–54

  View details for DOI 10.1515/nanoph-2020-0444

  View details for Web of Science ID 000597359300053

• Exciton Resonance Tuning in Atomically-Thin Optical Elements van de Groep, J., Song, J., Li, Q., Celano, U., Kik, P. G., Brongersma, M. L., IEEE IEEE. 2021

  View details for Web of Science ID 000831479802173

• Quantitative Phase Contrast Imaging using Guided-mode Resonator Devices Ji, A., Song, J., Li, Q., Kik, P. G., Miller, D. B., Brongersma, M. L., IEEE IEEE. 2021

  View details for Web of Science ID 000831479803156

• Direct laser writing of volumetric gradient index lenses and waveguides. Light, science & applications Ocier, C. R., Richards, C. A., Bacon-Brown, D. A., Ding, Q., Kumar, R., Garcia, T. J., van de Groep, J., Song, J., Cyphersmith, A. J., Rhode, A., Perry, A. N., Littlefield, A. J., Zhu, J., Xie, D., Gao, H., Messinger, J. F., Brongersma, M. L., Toussaint, K. C., Goddard, L. L., Braun, P. V. 2020; 9 (1): 196

  Abstract

  Direct laser writing (DLW) has been shown to render 3D polymeric optical components, including lenses, beam expanders, and mirrors, with submicrometer precision. However, these printed structures are limited to the refractive index and dispersive properties of the photopolymer. Here, we present the subsurface controllable refractive index via beam exposure (SCRIBE) method, a lithographic approach that enables the tuning of the refractive index over a range of greater than 0.3 by performing DLW inside photoresist-filled nanoporous silicon and silica scaffolds. Adjusting the laser exposure during printing enables 3D submicron control of the polymer infilling and thus the refractive index and chromatic dispersion. Combining SCRIBE's unprecedented index range and 3D writing accuracy has realized the world's smallest (15m diameter) spherical Luneburg lens operating at visible wavelengths. SCRIBE's ability to tune the chromatic dispersion alongside the refractive index was leveraged to render achromatic doublets in a single printing step, eliminating the need for multiple photoresins and writing sequences. SCRIBE also has the potential to form multicomponent optics by cascading optical elements within a scaffold. As a demonstration, stacked focusing structures that generate photonic nanojets were fabricated inside porous silicon. Finally, an all-pass ring resonator was coupled to a subsurface 3D waveguide. The measured quality factor of 4600 at 1550nm suggests the possibility of compact photonic systems with optical interconnects that traverse multiple planes. SCRIBE is uniquely suited for constructing such photonic integrated circuits due to its ability to integrate multiple optical components, including lenses and waveguides, without additional printed supports.

  View details for DOI 10.1038/s41377-020-00431-3

  View details for PubMedID 33298832

• Monolithic Full-Stokes Near-Infrared Polarimetry with Chiral Plasmonic Metasurface Integrated Graphene-Silicon Photodetector. ACS nano Li, L., Wang, J., Kang, L., Liu, W., Yu, L., Zheng, B., Brongersma, M. L., Werner, D. H., Lan, S., Shi, Y., Xu, Y., Wang, X. 2020

  Abstract

  The ability to detect the full-Stokes polarization of light is vital for a variety of applications that often require complex and bulky optical systems. Here, we report an on-chip polarimeter comprising four metasurface-integrated graphene-silicon photodetectors. The geometric chirality and anisotropy of the metasurfaces result in circular and linear polarization-resolved photoresponses, from which the full-Stokes parameters, including the intensity, orientation, and ellipticity of arbitrarily polarized incident infrared light (1550 nm), can be obtained. The design presents an ultracompact architecture while excluding the standard bulky optical components and structural redundancy. Computational extraction of full-Stokes parameters from mutual information among four detectors eliminates the need for a large absorption contrast between different polarization states. Our monolithic plasmonic metasurface integrated polarimeter is ideal for a variety of polarization-based applications including biological sensing, quantum information processing, and polarization photography.

  View details for DOI 10.1021/acsnano.0c00724

  View details for PubMedID 33197172

• All-solid-state spatial light modulator with independent phase and amplitude control for three-dimensional LiDAR applications. Nature nanotechnology Park, J., Jeong, B. G., Kim, S. I., Lee, D., Kim, J., Shin, C., Lee, C. B., Otsuka, T., Kyoung, J., Kim, S., Yang, K., Park, Y., Lee, J., Hwang, I., Jang, J., Song, S. H., Brongersma, M. L., Ha, K., Hwang, S., Choo, H., Choi, B. L. 2020

  Abstract

  Spatial light modulators are essential optical elements in applications that require the ability to regulate the amplitude, phase and polarization of light, such as digital holography, optical communications and biomedical imaging. With the push towards miniaturization of optical components, static metasurfaces are used as competent alternatives. These evolved to active metasurfaces in which light-wavefront manipulation can be done in a time-dependent fashion. The active metasurfaces reported so far, however, still show incomplete phase modulation (below 360°). Here we present an all-solid-state, electrically tunable and reflective metasurface array that can generate a specific phase or a continuous sweep between 0 and 360° at an estimated rate of 5.4MHz while independently adjusting the amplitude. The metasurface features 550 individually addressable nanoresonators in a 250*250mum2 area with no micromechanical elements or liquid crystals. A key feature of our design is the presence of two independent control parameters (top and bottom gate voltages) in each nanoresonator, which are used to adjust the real and imaginary parts of the reflection coefficient independently. To demonstrate this array's use in light detection and ranging, we performed a three-dimensional depth scan of an emulated street scene that consisted of a model car and a human figure up to a distance of 4.7m.

  View details for DOI 10.1038/s41565-020-00787-y

  View details for PubMedID 33106642

• An Over-Coupled Phase-Change Metasurface for Efficient Reflection Phase Modulation ADVANCED OPTICAL MATERIALS Park, J., Kim, S., Landreman, P., Brongersma, M. L. 2020

  View details for DOI 10.1002/adom.202000745

  View details for Web of Science ID 000562398600001

• High quality factor phase gradient metasurfaces. Nature nanotechnology Lawrence, M., Barton, D. R., Dixon, J., Song, J., van de Groep, J., Brongersma, M. L., Dionne, J. A. 2020

  Abstract

  Dielectric microcavities with quality factors (Q-factors) in the thousands to billions markedly enhance light-matter interactions, with applications spanning high-efficiency on-chip lasing, frequency comb generation and modulation and sensitive molecular detection. However, as the dimensions of dielectric cavities are reduced to subwavelength scales, their resonant modes begin to scatter light into many spatial channels. Such enhanced scattering is a powerful tool for light manipulation, but also leads to high radiative loss rates and commensurately low Q-factors, generally of order ten. Here, we describe and experimentally demonstrate a strategy for the generation of high Q-factor resonances in subwavelength-thick phase gradient metasurfaces. By including subtle structural perturbations in individual metasurface elements, resonances are created that weakly couple free-space light into otherwise bound and spatially localized modes. Our metasurface can achieve Q-factors >2,500 while beam steering light to particular directions. High-Q beam splitters are also demonstrated. With high-Q metasurfaces, the optical transfer function, near-field intensity and resonant line shape can all be rationally designed, providing a foundation for efficient, free-space-reconfigurable and nonlinear nanophotonics.

  View details for DOI 10.1038/s41565-020-0754-x

  View details for PubMedID 32807879

• Free-standing 2.7 mu m thick ultrathin crystalline silicon solar cell with efficiency above 12.0% (vol 70, 104466, 2020) NANO ENERGY Xue, M., Nazif, K., Lyu, Z., Jiang, J., Lu, C., Lee, N., Zang, K., Chen, Y., Zheng, T., Kamins, T. I., Brongersma, M. L., Saraswat, K. C., Harris, J. S. 2020; 72

  View details for DOI 10.1016/j.nanoen.2020.104709

  View details for Web of Science ID 000532790600006

• Exciton resonance tuning of an atomically thin lens NATURE PHOTONICS van de Groep, J., Song, J., Celano, U., Li, Q., Kik, P. G., Brongersma, M. L. 2020

  View details for DOI 10.1038/s41566-020-0624-y

  View details for Web of Science ID 000529001600001

• Free-standing 2.7 mu m thick ultrathin crystalline silicon solar cell with efficiency above 12.0% NANO ENERGY Xue, M., Nazif, K., Lyu, Z., Jiang, J., Lu, C., Lee, N., Zang, K., Chen, Y., Zheng, T., Kamins, T., Brongersma, M. L., Saraswat, K. C., Harris, J. S. 2020; 70

  View details for DOI 10.1016/j.nanoen.2020.104466

  View details for Web of Science ID 000521052900040

• Strained bilayer WSe2 with reduced exciton-phonon coupling PHYSICAL REVIEW B Asian, O., Deng, M., Brongersma, M. L., Heinz, T. F. 2020; 101 (11)

  View details for DOI 10.1103/PhysRevB.101.115305

  View details for Web of Science ID 000521084000001

• Electrotunable liquid sulfur microdroplets. Nature communications Zhou, G. n., Yang, A. n., Wang, Y. n., Gao, G. n., Pei, A. n., Yu, X. n., Zhu, Y. n., Zong, L. n., Liu, B. n., Xu, J. n., Liu, N. n., Zhang, J. n., Li, Y. n., Wang, L. W., Hwang, H. Y., Brongersma, M. L., Chu, S. n., Cui, Y. n. 2020; 11 (1): 606

  Abstract

  Manipulating liquids with tunable shape and optical functionalities in real time is important for electroactive flow devices and optoelectronic devices, but remains a great challenge. Here, we demonstrate electrotunable liquid sulfur microdroplets in an electrochemical cell. We observe electrowetting and merging of sulfur droplets under different potentiostatic conditions, and successfully control these processes via selective design of sulfiphilic/sulfiphobic substrates. Moreover, we employ the electrowetting phenomena to create a microlens based on the liquid sulfur microdroplets and tune its characteristics in real time through changing the shape of the liquid microdroplets in a fast, repeatable, and controlled manner. These studies demonstrate a powerful in situ optical battery platform for unraveling the complex reaction mechanism of sulfur chemistries and for exploring the rich material properties of the liquid sulfur, which shed light on the applications of liquid sulfur droplets in devices such as microlenses, and potentially other electrotunable and optoelectronic devices.

  View details for DOI 10.1038/s41467-020-14438-2

  View details for PubMedID 32001696

• Metasurface-driven OLED displays beyond 10,000 pixels per inch. Science (New York, N.Y.) Joo, W. J., Kyoung, J. n., Esfandyarpour, M. n., Lee, S. H., Koo, H. n., Song, S. n., Kwon, Y. N., Song, S. H., Bae, J. C., Jo, A. n., Kwon, M. J., Han, S. H., Kim, S. H., Hwang, S. n., Brongersma, M. L. 2020; 370 (6515): 459–63

  Abstract

  Optical metasurfaces are starting to find their way into integrated devices, where they can enhance and control the emission, modulation, dynamic shaping, and detection of light waves. In this study, we show that the architecture of organic light-emitting diode (OLED) displays can be completely reenvisioned through the introduction of nanopatterned metasurface mirrors. In the resulting meta-OLED displays, different metasurface patterns define red, green, and blue pixels and ensure optimized extraction of these colors from organic, white light emitters. This new architecture facilitates the creation of devices at the ultrahigh pixel densities (>10,000 pixels per inch) required in emerging display applications (for instance, augmented reality) that use scalable nanoimprint lithography. The fabricated pixels also offer twice the luminescence efficiency and superior color purity relative to standard color-filtered white OLEDs.

  View details for DOI 10.1126/science.abc8530

  View details for PubMedID 33093108

• Transparent multispectral photodetectors mimicking the human visual system. Nature communications Li, Q., van de Groep, J., Wang, Y., Kik, P. G., Brongersma, M. L. 2019; 10 (1): 4982

  Abstract

  Compact and lightweight photodetection elements play a critical role in the newly emerging augmented reality, wearable and sensing technologies. In these technologies, devices are preferred to be transparent to form an optical interface between a viewer and the outside world. For this reason, it is of great value to create detection platforms that are imperceptible to the human eye directly onto transparent substrates. Semiconductor nanowires (NWs) make ideal photodetectors as their optical resonances enable parsing of the multi-dimensional information carried by light. Unfortunately, these optical resonances also give rise to strong, undesired light scattering. In this work, we illustrate how a new optical resonance arising from the radiative coupling between arrayed silicon NWs can be harnessed to remove reflections from dielectric interfaces while affording spectro-polarimetric detection. The demonstrated transparent photodetector concept opens up promising platforms for transparent substrates as the base for opto-electronic devices and in situoptical measurement systems.

  View details for DOI 10.1038/s41467-019-12899-8

  View details for PubMedID 31676782

• Spin-Switched Three-Dimensional Full-Color Scenes Based on a Dielectric Meta-hologram ACS PHOTONICS Feng, H., Li, Q., Wan, W., Song, J., Gong, Q., Brongersma, M. L., Li, Y. 2019; 6 (11): 2910–16

  View details for DOI 10.1021/acsphotonics.9b01017

  View details for Web of Science ID 000499742000037

• Anisotropic Metasurfaces as Tunable SERS Substrates for 2D Materials ACS PHOTONICS Thareja, V., Esfandyarpour, M., Kik, P. G., Brongersma, M. L. 2019; 6 (8): 1996–2004

  View details for DOI 10.1021/acsphotonics.9b00416

  View details for Web of Science ID 000482545400024

• A Light-Field Metasurface for High-Resolution Single-Particle Tracking NANO LETTERS Holsteen, A. L., Lin, D., Kauvar, I., Wetzstein, G., Brongersma, M. L. 2019; 19 (4): 2267–71

  View details for DOI 10.1021/acs.nanolett.8b04673

  View details for Web of Science ID 000464769100010

• A Light-Field Metasurface for High-Resolution Single-Particle Tracking. Nano letters Holsteen, A. L., Lin, D., Kauvar, I., Wetzstein, G., Brongersma, M. L. 2019

  Abstract

  Three-dimensional (3D) single-particle tracking (SPT) is a key tool for studying dynamic processes in the life sciences. However, conventional optical elements utilizing light fields impose an inherent trade-off between lateral and axial resolution, preventing SPT with high spatiotemporal resolution across an extended volume. We overcome the typical loss in spatial resolution that accompanies light-field-based approaches to obtain 3D information by placing a standard microscope coverslip patterned with a multifunctional, light-field metasurface on a specimen. This approach enables an otherwise unmodified microscope to gather 3D information at an enhanced spatial resolution. We demonstrate simultaneous tracking of multiple fluorescent particles within a large 0.5 * 0.5 * 0.3 mm3 volume using a standard epi-fluorescent microscope with submicron lateral and micron-level axial resolution.

  View details for PubMedID 30897902

• Probing the Band Structure of Topological Silicon Photonic Lattices in the Visible Spectrum. Physical review letters Peng, S., Schilder, N. J., Ni, X., van de Groep, J., Brongersma, M. L., Alù, A., Khanikaev, A. B., Atwater, H. A., Polman, A. 2019; 122 (11): 117401

  Abstract

  We study two-dimensional hexagonal photonic lattices of silicon Mie resonators with a topological optical band structure in the visible spectral range. We use 30 keV electrons focused to nanoscale spots to map the local optical density of states in topological photonic lattices with deeply subwavelength resolution. By slightly shrinking or expanding the unit cell, we form hexagonal superstructures and observe the opening of a band gap and a splitting of the double-degenerate Dirac cones, which correspond to topologically trivial and nontrivial phases. Optical transmission spectroscopy shows evidence of topological edge states at the domain walls between topological and trivial lattices.

  View details for DOI 10.1103/PhysRevLett.122.117401

  View details for PubMedID 30951323

• Probing the Band Structure of Topological Silicon Photonic Lattices in the Visible Spectrum PHYSICAL REVIEW LETTERS Peng, S., Schilder, N. J., Ni, X., van de Groep, J., Brongersma, M. L., Alu, A., Khanikaev, A. B., Atwater, H. A., Polman, A. 2019; 122 (11)

  View details for DOI 10.1103/PhysRevLett.122.117401

  View details for Web of Science ID 000461923000012

• Antireflection High-Index Metasurfaces Combining Mie and Fabry-Perot Resonances ACS PHOTONICS Cordaro, A., van de Groep, J., Raza, S., Pecora, E., Priolo, F., Brongersma, M. L. 2019; 6 (2): 453–59

  View details for DOI 10.1021/acsphotonics.8b01406

  View details for Web of Science ID 000459642800029

• Subwavelength angle-sensing photodetectors inspired by internally coupled ears in small animals Yi, S., Zhou, M., Yu, Z., Fan, P., Behdad, N., Lin, D., Wang, K., Fan, S., Brongersm, M., Panchapakesan, B., Attias, A. J. SPIE-INT SOC OPTICAL ENGINEERING. 2019

  View details for DOI 10.1117/12.2529594

  View details for Web of Science ID 000502134800007

• Dynamic Tuning of Gap Plasmon Resonances Using a Solid-State Electrochromic Device. Nano letters Li, Y. n., van de Groep, J. n., Talin, A. A., Brongersma, M. L. 2019

  Abstract

  Plasmonic antennas and metasurfaces can effectively control light-matter interactions, and this facilitates a deterministic design of optical materials properties, including structural color. However, these optical properties are generally fixed after synthesis and fabrication, while many modern-day optics applications require active, low-power, and nonvolatile tuning. These needs have spurred broad research activities aimed at identifying materials and resonant structures capable of achieving large, dynamic changes in optical properties, especially in the challenging visible spectral range. In this work, we demonstrate dynamic tuning of polarization-dependent gap plasmon resonators that contain the electrochromic oxide WO3. Its refractive index in the visible changes continuously from n = 2.1 to 1.9 upon electrochemical lithium insertion and removal in a solid-state device. By incorporating WO3 into a gap plasmon resonator, the resonant wavelength can be shifted continuously and reversibly by up to 58 nm with less than 2 V electrochemical bias voltage. The resonator can remain in a tuned state for tens of minutes under open circuit conditions.

  View details for DOI 10.1021/acs.nanolett.9b03143

  View details for PubMedID 31560552

• Spatiotemporal light control with active metasurfaces. Science (New York, N.Y.) Shaltout, A. M., Shalaev, V. M., Brongersma, M. L. 2019; 364 (6441)

  Abstract

  Optical metasurfaces have provided us with extraordinary ways to control light by spatially structuring materials. The space-time duality in Maxwell's equations suggests that additional structuring of metasurfaces in the time domain can even further expand their impact on the field of optics. Advances toward this goal critically rely on the development of new materials and nanostructures that exhibit very large and fast changes in their optical properties in response to external stimuli. New physics is also emerging as ultrafast tuning of metasurfaces is becoming possible, including wavelength shifts that emulate the Doppler effect, Lorentz nonreciprocity, time-reversed optical behavior, and negative refraction. The large-scale manufacturing of dynamic flat optics has the potential to revolutionize many emerging technologies that require active wavefront shaping with lightweight, compact, and power-efficient components.

  View details for DOI 10.1126/science.aat3100

  View details for PubMedID 31097638

• Spatiotemporal light control with frequency-gradient metasurfaces. Science (New York, N.Y.) Shaltout, A. M., Lagoudakis, K. G., van de Groep, J. n., Kim, S. J., Vučković, J. n., Shalaev, V. M., Brongersma, M. L. 2019; 365 (6451): 374–77

  Abstract

  The capability of on-chip wavefront modulation has the potential to revolutionize many optical device technologies. However, the realization of power-efficient phase-gradient metasurfaces that offer full-phase modulation (0 to 2π) and high operation speeds remains elusive. We present an approach to continuously steer light that is based on creating a virtual frequency-gradient metasurface by combining a passive metasurface with an advanced frequency-comb source. Spatiotemporal redirection of light naturally occurs as optical phase-fronts reorient at a speed controlled by the frequency gradient across the virtual metasurface. An experimental realization of laser beam steering with a continuously changing steering angle is demonstrated with a single metasurface over an angle of 25° in just 8 picoseconds. This work can support integrated-on-chip solutions for spatiotemporal optical control, directly affecting emerging applications such as solid-state light detection and ranging (LIDAR), three-dimensional imaging, and augmented or virtual systems.

  View details for DOI 10.1126/science.aax2357

  View details for PubMedID 31346064

• Temporal color mixing and dynamic beam shaping with silicon metasurfaces. Science (New York, N.Y.) Holsteen, A. L., Cihan, A. F., Brongersma, M. L. 2019; 365 (6450): 257–60

  Abstract

  Metasurfaces offer the possibility to shape optical wavefronts with an ultracompact, planar form factor. However, most metasurfaces are static, and their optical functions are fixed after the fabrication process. Many modern optical systems require dynamic manipulation of light, and this is now driving the development of electrically reconfigurable metasurfaces. We can realize metasurfaces with fast (>105 hertz), electrically tunable pixels that offer complete (0- to 2π) phase control and large amplitude modulation of scattered waves through the microelectromechanical movement of silicon antenna arrays created in standard silicon-on-insulator technology. Our approach can be used to realize a platform technology that enables low-voltage operation of pixels for temporal color mixing and continuous, dynamic beam steering and light focusing.

  View details for DOI 10.1126/science.aax5961

  View details for PubMedID 31320534

• Reversible and selective ion intercalation through the top surface of few-layer MoS2. Nature communications Zhang, J., Yang, A., Wu, X., van de Groep, J., Tang, P., Li, S., Liu, B., Shi, F., Wan, J., Li, Q., Sun, Y., Lu, Z., Zheng, X., Zhou, G., Wu, C., Zhang, S., Brongersma, M. L., Li, J., Cui, Y. 2018; 9 (1): 5289

  Abstract

  Electrochemical intercalation of ions into the van der Waals gap of two-dimensional (2D) layered materials is a promising low-temperature synthesis strategy to tune their physical and chemical properties. It is widely believed that ions prefer intercalation into the van der Waals gap through the edges of the 2D flake, which generally causes wrinkling and distortion. Here we demonstrate that the ions can also intercalate through the top surface of few-layer MoS2 and this type of intercalation is more reversible and stable compared to the intercalation through the edges. Density functional theory calculations show that this intercalation is enabled by the existence of natural defects in exfoliated MoS2 flakes. Furthermore, we reveal that sealed-edge MoS2 allows intercalation of small alkali metal ions (e.g., Li+ and Na+) and rejects large ions (e.g., K+). These findings imply potential applications in developing functional 2D-material-based devices with high tunability and ion selectivity.

  View details for PubMedID 30538249

• Reversible and selective ion intercalation through the top surface of few-layer MoS2 NATURE COMMUNICATIONS Zhang, J., Yang, A., Wu, X., van de Groep, J., Tang, P., Li, S., Liu, B., Shi, F., Wan, J., Li, Q., Sun, Y., Lu, Z., Zheng, X., Zhou, G., Wu, C., Zhang, S., Brongersma, M. L., Li, J., Cui, Y. 2018; 9

  View details for DOI 10.1038/s41467-018-07710-z

  View details for Web of Science ID 000452777900013

• Dynamic thermal emission control with InAs-based plasmonic metasurfaces. Science advances Park, J., Kang, J., Liu, X., Maddox, S. J., Tang, K., McIntyre, P. C., Bank, S. R., Brongersma, M. L. 2018; 4 (12): eaat3163

  Abstract

  Thermal emission from objects tends to be spectrally broadband, unpolarized, and temporally invariant. These common notions are now challenged with the emergence of new nanophotonic structures and concepts that afford on-demand, active manipulation of the thermal emission process. This opens a myriad of new applications in chemistry, health care, thermal management, imaging, sensing, and spectroscopy. Here, we theoretically propose and experimentally demonstrate a new approach to actively tailor thermal emission with a reflective, plasmonic metasurface in which the active material and reflector element are epitaxially grown, high-carrier-mobility InAs layers. Electrical gating induces changes in the charge carrier density of the active InAs layer that are translated into large changes in the optical absorption and thermal emission from metasurface. We demonstrate polarization-dependent and electrically controlled emissivity changes of 3.6%P (6.5% in relative scale) in the mid-infrared spectral range.

  View details for PubMedID 30539139

• Subwavelength angle-sensing photodetectors inspired by directional hearing in small animals (vol 13, pg 1143, 2018) NATURE NANOTECHNOLOGY Yi, S., Zhou, M., Yu, Z., Fan, P., Behdad, N., Lin, D., Wang, K., Fan, S., Brongersma, M. 2018; 13 (12): 1191

  View details for DOI 10.1038/s41565-018-0322-9

  View details for Web of Science ID 000452408300026

• Dynamic thermal emission control with InAs-based plasmonic metasurfaces SCIENCE ADVANCES Park, J., Kang, J., Liu, X., Maddox, S. J., Tang, K., McIntyre, P. C., Bank, S. R., Brongersma, M. L. 2018; 4 (12)

  View details for DOI 10.1126/sciadv.aat3163

  View details for Web of Science ID 000454369600001

• Subwavelength angle-sensing photodetectors inspired by directional hearing in small animals NATURE NANOTECHNOLOGY Yi, S., Zhou, M., Yu, Z., Fan, P., Behdad, N., Lin, D., Wang, K., Fan, S., Brongersma, M. 2018; 13 (12): 1143-+

  View details for DOI 10.1038/s41565-018-0278-9

  View details for Web of Science ID 000452408300018

• Order and Disorder Embedded in a Spectrally Interleaved Metasurface ACS PHOTONICS Yannai, M., Maguid, E., Faerman, A., Li, Q., Song, J., Kleiner, V., Brongersma, M. L., Hasman, E. 2018; 5 (12): 4764–68

  View details for DOI 10.1021/acsphotonics.8b01138

  View details for Web of Science ID 000454463000007

• Spectrally interleaved topologies using geometric phase metasurfaces OPTICS EXPRESS Yannai, M., Maguid, E., Faerman, A., Li, Q., Song, J., Kleiner, V., Brongersma, M. L., Hasman, E. 2018; 26 (23): 31031–38

  Abstract

  Metasurfaces facilitate the interleaving of multiple topologies in an ultra-thin photonic system. Here, we report on the spectral interleaving of topological states of light using a geometric phase metasurface. We realize that a dielectric spectrally interleaved metasurface generates multiple interleaved vortex beams at different wavelengths. By harnessing the space-variant polarization manipulations that are enabled by the geometric phase mechanism, a vectorial vortex array is implemented. The presented interleaved topologies concept can greatly enhance the functionality of advanced microscopy and communication systems.

  View details for DOI 10.1364/OE.26.031031

  View details for Web of Science ID 000449972600116

  View details for PubMedID 30469990

• Broadband Antireflection Coatings Employing Multiresonant Dielectric Metasurfaces ACS PHOTONICS Pecora, E. F., Cordaro, A., Kik, P. G., Brongersma, M. L. 2018; 5 (11): 4456–62

  View details for DOI 10.1021/acsphotonics.8b00913

  View details for Web of Science ID 000451496500035

• DNA-Assembled Plasmonic Waveguides for Nanoscale Light Propagation to a Fluorescent Nanodiamond NANO LETTERS Guer, F. N., McPolin, C. T., Raza, S., Mayer, M., Roth, D. J., Steiner, A., Loeffler, M., Fery, A., Brongersma, M. L., Zayats, A. V., Koenig, T. F., Schmidt, T. L. 2018; 18 (11): 7323-7329

  View details for DOI 10.1021/acs.nanolett.8b03524

  View details for Web of Science ID 000451102100090

• Epsilon-Near-Zero Si Slot-Waveguide Modulator ACS PHOTONICS Liu, X., Zang, K., Kang, J., Park, J., Harris, J. S., Kik, P. G., Brongersma, M. L. 2018; 5 (11): 4484–90

  View details for DOI 10.1021/acsphotonics.8b00945

  View details for Web of Science ID 000451496500039

• Electrically Tunable, CMOS-Compatible Metamaterial Based on Semiconductor Nanopillars ACS PHOTONICS Morea, M., Zang, K., Kamins, T. I., Brongersma, M. L., Harris, J. S. 2018; 5 (11): 4702–9

  View details for DOI 10.1021/acsphotonics.8b01383

  View details for Web of Science ID 000451496500065

• Subwavelength angle-sensing photodetectors inspired by directional hearing in small animals. Nature nanotechnology Yi, S., Zhou, M., Yu, Z., Fan, P., Behdad, N., Lin, D., Wang, K. X., Fan, S., Brongersma, M. 2018

  Abstract

  Sensing the direction of sounds gives animals clear evolutionary advantage. For large animals, with an ear-to-ear spacing that exceeds audible sound wavelengths, directional sensing is simply accomplished by recognizing the intensity and time differences of a wave impinging on its two ears1. Recent research suggests that in smaller, subwavelength animals, angle sensing can instead rely on a coherent coupling of soundwaves between the two ears2-4. Inspired by this natural design, here we show a subwavelength photodetection pixel that can measure both the intensity and incident angle of light. It relies on an electrical isolation and optical coupling of two closely spaced Si nanowires that support optical Mie resonances5-7. When these resonators scatter light into the same free-space optical modes, a non-Hermitian coupling results that affords highly sensitive angle determination. By straightforward photocurrent measurements, we can independently quantify the stored optical energy in each nanowire and relate the difference in the stored energy between the wires to the incident angle of a light wave. We exploit this effect to fabricate a subwavelength angle-sensitive pixel with angular sensitivity, deltatheta=0.32°.

  View details for PubMedID 30374161

• DNA-Assembled Plasmonic Waveguides for Nanoscale Light Propagation to a Fluorescent Nanodiamond. Nano letters Gur, F. N., McPolin, C. P., Raza, S., Mayer, M., Roth, D. J., Steiner, A. M., Loffler, M., Fery, A., Brongersma, M. L., Zayats, A. V., Konig, T. A., Schmidt, T. L. 2018

  Abstract

  Plasmonic waveguides consisting of metal nanoparticle chains can localize and guide light well below the diffraction limit, but high propagation losses due to lithography-limited large interparticle spacing have impeded practical applications. Here, we demonstrate that DNA-origami-based self-assembly of monocrystalline gold nanoparticles allows the interparticle spacing to be decreased to 2 nm, thus reducing propagation losses to 0.8 dB per 50 nm at a deep subwavelength confinement of 62 nm (lambda/10). We characterize the individual waveguides with nanometer-scale resolution by electron energy-loss spectroscopy. Light propagation toward a fluorescent nanodiamond is directly visualized by cathodoluminescence imaging spectroscopy on a single-device level, thereby realizing nanoscale light manipulation and energy conversion. Simulations suggest that longitudinal plasmon modes arising from the narrow gaps are responsible for the efficient waveguiding. With this scalable DNA origami approach, micrometer-long propagation lengths could be achieved, enabling applications in information technology, sensing, and quantum optics.

  View details for PubMedID 30339400

• Polarization-independent metasurface lens employing the Pancharatnam-Berry phase OPTICS EXPRESS Lin, D., Holsteen, A. L., Maguid, E., Fan, P., Kik, P. G., Hasman, E., Brongersma, M. L. 2018; 26 (19): 24835–42

  View details for DOI 10.1364/OE.26.024835

  View details for Web of Science ID 000444705000045

• Optical emission near a high-impedance mirror. Nature communications Esfandyarpour, M., Curto, A. G., Kik, P. G., Engheta, N., Brongersma, M. L. 2018; 9 (1): 3224

  Abstract

  Solid state light emitters rely on metallic contacts with a high sheet-conductivity for effective charge injection. Unfortunately, such contacts also support surface plasmon polariton and lossy wave excitations that dissipate optical energy into the metal and limit the external quantum efficiency. Here, inspired by the concept of radio-frequency high-impedance surfaces and their use in conformal antennas we illustrate how electrodes can be nanopatterned to simultaneously provide a high DC electrical conductivity and high-impedance at optical frequencies. Such electrodes do not support SPPs across the visible spectrum and greatly suppress dissipative losses while facilitating a desirable Lambertian emission profile. We verify this concept by studying the emission enhancement and photoluminescence lifetime for a dye emitter layer deposited on the electrodes.

  View details for PubMedID 30104605

• Optical emission near a high-impedance mirror NATURE COMMUNICATIONS Esfandyarpour, M., Curto, A. G., Kik, P. G., Engheta, N., Brongersma, M. L. 2018; 9

  View details for DOI 10.1038/s41467-018-05505-w

  View details for Web of Science ID 000441382000002

• Electrochemical Fabrication of Flat, Polymer-Embedded Porous Silicon 1D Gradient Refractive Index Microlens Arrays Krueger, N. A., Holsteen, A. L., Zhao, Q., Kang, S., Ocier, C. R., Zhou, W., Mensing, G., Rogers, J. A., Brongersma, M. L., Braun, P. V. WILEY-V C H VERLAG GMBH. 2018

  View details for DOI 10.1002/pssa.201800088

  View details for Web of Science ID 000438358000025

• Metasurface Mirrors for External Control of Mie Resonances NANO LETTERS van de Groep, J., Brongersma, M. L. 2018; 18 (6): 3857-3864

  View details for DOI 10.1021/acs.nanolett.8b01148

  View details for Web of Science ID 000435524300077

• Metasurface Mirrors for External Control of Mie Resonances. Nano letters van de Groep, J., Brongersma, M. L. 2018

  Abstract

  The ability to control and structurally tune the optical resonances of semiconductor nanostructures has far-reaching implications for a wide range of optical applications, including photodetectors, (bio)sensors, and photovoltaics. Such control is commonly obtained by tailoring the nanostructure's geometry, material, or dielectric environment. Here, we combine insights from the field of coherent optics and metasurface mirrors to effectively turn Mie resonances on and off with high spatial control and in a polarization-dependent fashion. We illustrate this in an integrated device by manipulating the photocurrent spectra of a single-nanowire photodetector placed on a metasurface mirror. This approach can be generalized to control spectral, angle-dependent, absorption, and scattering properties of semiconductor nanostructures with an engineered metasurface and without a need to alter their geometric or materials properties.

  View details for PubMedID 29787285

• Silicon Mie resonators for highly directional light emission from monolayer MoS2 NATURE PHOTONICS Cihan, A., Curto, A. G., Raza, S., Kik, P. G., Brongersma, M. L. 2018; 12 (5): 284-+

  View details for DOI 10.1038/s41566-018-0155-y

  View details for Web of Science ID 000431168200015

• Spatially controlled doping of two-dimensional SnS2 through intercalation for electronics NATURE NANOTECHNOLOGY Gong, Y., Yuan, H., Wu, C., Tang, P., Yang, S., Yang, A., Li, G., Liu, B., van de Groep, J., Brongersma, M. L., Chisholm, M. F., Zhang, S., Zhou, W., Cui, Y. 2018; 13 (4): 294-+

  Abstract

  Doped semiconductors are the most important building elements for modern electronic devices 1 . In silicon-based integrated circuits, facile and controllable fabrication and integration of these materials can be realized without introducing a high-resistance interface2,3. Besides, the emergence of two-dimensional (2D) materials enables the realization of atomically thin integrated circuits4-9. However, the 2D nature of these materials precludes the use of traditional ion implantation techniques for carrier doping and further hinders device development 10 . Here, we demonstrate a solvent-based intercalation method to achieve p-type, n-type and degenerately doped semiconductors in the same parent material at the atomically thin limit. In contrast to naturally grown n-type S-vacancy SnS2, Cu intercalated bilayer SnS2 obtained by this technique displays a hole field-effect mobility of ~40 cm2 V-1 s-1, and the obtained Co-SnS2 exhibits a metal-like behaviour with sheet resistance comparable to that of few-layer graphene 5 . Combining this intercalation technique with lithography, an atomically seamless p-n-metal junction could be further realized with precise size and spatial control, which makes in-plane heterostructures practically applicable for integrated devices and other 2D materials. Therefore, the presented intercalation method can open a new avenue connecting the previously disparate worlds of integrated circuits and atomically thin materials.

  View details for PubMedID 29483599

• Tuning of Plasmons in Transparent Conductive Oxides by Carrier Accumulation ACS PHOTONICS Liu, X., Kang, J., Yuan, H., Park, J., Cui, Y., Hwang, H. Y., Brongersma, M. L. 2018; 5 (4): 1493–98

  View details for DOI 10.1021/acsphotonics.7b01517

  View details for Web of Science ID 000430642500044

• Thermoplasmonic Ignition of Metal Nanoparticles NANO LETTERS Mutlu, M., Kang, J., Raza, S., Schoen, D., Zheng, X., Kik, P. G., Brongersma, M. L. 2018; 18 (3): 1699–1706

  Abstract

  Explosives, propellants, and pyrotechnics are energetic materials that can store and quickly release tremendous amounts of chemical energy. Aluminum (Al) is a particularly important fuel in many applications because of its high energy density, which can be released in a highly exothermic oxidation process. The diffusive oxidation mechanism (DOM) and melt-dispersion mechanism (MDM) explain the ways powders of Al nanoparticles (NPs) can burn, but little is known about the possible use of plasmonic resonances in NPs to manipulate photoignition. This is complicated by the inhomogeneous nature of powders and very fast heating and burning rates. Here, we generate Al NPs with well-defined sizes, shapes, and spacings by electron beam lithography and demonstrate that their plasmonic resonances can be exploited to heat and ignite them with a laser. By combining simulations with thermal-emission, electron-, and optical-microscopy studies, we reveal how an improved control over NP ignition can be attained.

  View details for PubMedID 29356548

• Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting NATURE COMMUNICATIONS Kim, S., Kang, J., Mutlu, M., Park, J., Park, W., Goodson, K. E., Sinclair, R., Fan, S., Kik, P. G., Brongersma, M. L. 2018; 9: 316

  Abstract

  The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons.

  View details for PubMedID 29358626

• Purcell effect for active tuning of light scattering from semiconductor optical antennas SCIENCE Holsteen, A. L., Raza, S., Fan, P., Kik, P. G., Brongersma, M. L. 2017; 358 (6369): 1407–10

  Abstract

  Subwavelength, high-refractive index semiconductor nanostructures support optical resonances that endow them with valuable antenna functions. Control over the intrinsic properties, including their complex refractive index, size, and geometry, has been used to manipulate fundamental light absorption, scattering, and emission processes in nanostructured optoelectronic devices. In this study, we harness the electric and magnetic resonances of such antennas to achieve a very strong dependence of the optical properties on the external environment. Specifically, we illustrate how the resonant scattering wavelength of single silicon nanowires is tunable across the entire visible spectrum by simply moving the height of the nanowires above a metallic mirror. We apply this concept by using a nanoelectromechanical platform to demonstrate active tuning.

  View details for PubMedID 29242341

• Metasurface electrode light emitting diodes with planar light control SCIENTIFIC REPORTS Park, Y., Kim, J., Cho, K., Kim, H., Lee, M., Lee, J., Kim, U., Hwang, S., Brongersma, M. L., Roh, Y., Park, Q. 2017; 7: 14753

  Abstract

  The ability of metasurfaces to manipulate light at the subwavelength scale offers unprecedented functionalities for passive and active lasing devices. However, applications of metasurfaces to optical devices are rare due to fabrication difficulties. Here, we present quantum dot light emitting diodes (QDLEDs) with a metasurface-integrated metal electrode and demonstrate microscopically controlled LED emission. By incorporating slot-groove antennas into the metal electrode, we show that LED emission from randomly polarized QD sources can be polarized and directed at will. Utilizing the relation between polarization and emission direction, we also demonstrate microscopic LED beam splitting through the selective choice of polarization.

  View details for PubMedID 29116150

• Free-Space Optical Beam Tapping with an All-Silica Metasurface ACS PHOTONICS Li, Q., Dong, F., Wang, B., Chu, W., Gong, Q., Brongersma, M. L., Li, Y. 2017; 4 (10): 2544–49

  View details for DOI 10.1021/acsphotonics.7b00812

  View details for Web of Science ID 000413502900022

• Electrical tuning of a quantum plasmonic resonance NATURE NANOTECHNOLOGY Liu, X., Kang, H., Yuan, H., Park, J., Kim, S., Cui, Y., Hwang, H. Y., Brongersma, M. L. 2017; 12 (9): 866-+

  Abstract

  Surface plasmon (SP) excitations in metals facilitate confinement of light into deep-subwavelength volumes and can induce strong light-matter interaction. Generally, the SP resonances supported by noble metal nanostructures are explained well by classical models, at least until the nanostructure size is decreased to a few nanometres, approaching the Fermi wavelength λF of the electrons. Although there is a long history of reports on quantum size effects in the plasmonic response of nanometre-sized metal particles, systematic experimental studies have been hindered by inhomogeneous broadening in ensemble measurements, as well as imperfect control over size, shape, faceting, surface reconstructions, contamination, charging effects and surface roughness in single-particle measurements. In particular, observation of the quantum size effect in metallic films and its tuning with thickness has been challenging as they only confine carriers in one direction. Here, we show active tuning of quantum size effects in SP resonances supported by a 20-nm-thick metallic film of indium tin oxide (ITO), a plasmonic material serving as a low-carrier-density Drude metal. An ionic liquid (IL) is used to electrically gate and partially deplete the ITO layer. The experiment shows a controllable and reversible blue-shift in the SP resonance above a critical voltage. A quantum-mechanical model including the quantum size effect reproduces the experimental results, whereas a classical model only predicts a red shift.

  View details for PubMedID 28604706

• Multifunctional interleaved geometric-phase dielectric metasurfaces LIGHT-SCIENCE & APPLICATIONS Maguid, E., Yulevich, I., Yannai, M., Kleiner, V., Brongersma, M. L., Hasman, E. 2017; 6: e17027

  Abstract

  Shared-aperture technology for multifunctional planar systems, performing several simultaneous tasks, was first introduced in the field of radar antennas. In photonics, effective control of the electromagnetic response can be achieved by a geometric-phase mechanism implemented within a metasurface, enabling spin-controlled phase modulation. The synthesis of the shared-aperture and geometric-phase concepts facilitates the generation of multifunctional metasurfaces. Here shared-aperture geometric-phase metasurfaces were realized via the interleaving of sparse antenna sub-arrays, forming Si-based devices consisting of multiplexed geometric-phase profiles. We study the performance limitations of interleaved nanoantenna arrays by means of a Wigner phase-space distribution to establish the ultimate information capacity of a metasurface-based photonic system. Within these limitations, we present multifunctional spin-dependent dielectric metasurfaces, and demonstrate multiple-beam technology for optical rotation sensing. We also demonstrate the possibility of achieving complete real-time control and measurement of the fundamental, intrinsic properties of light, including frequency, polarization and orbital angular momentum.

  View details for PubMedID 30167279

• Applying plasmonics to a sustainable future. Science (New York, N.Y.) Naldoni, A., Shalaev, V. M., Brongersma, M. L. 2017; 356 (6341): 908-909

  View details for DOI 10.1126/science.aan5802

  View details for PubMedID 28572352

• Optical metasurfaces for high angle steering at visible wavelengths SCIENTIFIC REPORTS Lin, D., Melli, M., Poliakov, E., St Hilaire, P., Dhuey, S., Peroz, C., Cabrini, S., Brongersma, M., Klug, M. 2017; 7: 2286

  Abstract

  Metasurfaces have facilitated the replacement of conventional optical elements with ultrathin and planar photonic structures. Previous designs of metasurfaces were limited to small deflection angles and small ranges of the angle of incidence. Here, we have created two types of Si-based metasurfaces to steer visible light to a large deflection angle. These structures exhibit high diffraction efficiencies over a broad range of angles of incidence. We have demonstrated metasurfaces working both in transmission and reflection modes based on conventional thin film silicon processes that are suitable for the large-scale fabrication of high-performance devices.

  View details for PubMedID 28536465

• Device applications of metafilms Brongersma, M. AMER CHEMICAL SOC. 2017

  View details for Web of Science ID 000430569106700

• Observing Plasmon Damping Due to Adhesion Layers in Gold Nanostructures Using Electron Energy Loss Spectroscopy. ACS photonics Madsen, S. J., Esfandyarpour, M., Brongersma, M. L., Sinclair, R. 2017; 4 (2): 268-274

  Abstract

  Gold plasmonic nanostructures with several different adhesion layers have been studied with monochromated electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and with surface enhanced Raman spectroscopy (SERS). Compared to samples with no adhesion layer, those with 2nm of Cr or Ti show broadened, lower intensity plasmon peaks as measured with EELS. This broadening is observed in both optically active ("bright") and inactive ("dark") plasmon modes. When the former are probed with SERS, the signal enhancement factor is lower for samples with Cr or Ti, another indication of reduced plasmon resonance. This work illustrates the capability of STEM-EELS to provide direct near-field measurement of changes in plasmon excitation probability with nano-scale spatial resolution. Additionally, it demonstrates that applications which require high SERS enhancement, such as biomarker detection and cancer diagnostics, can be improved by avoiding the use of a metallic adhesion layer.

  View details for DOI 10.1021/acsphotonics.6b00525

  View details for PubMedID 28944259

  View details for PubMedCentralID PMC5604478

• Observing Plasmon Damping Due to Adhesion Layers in Gold Nanostructures Using Electron Energy Loss Spectroscopy ACS PHOTONICS Madsen, S. J., Esfandyarpour, M., Brongersma, M. L., Sinclair, R. 2017; 4 (2): 268-274

  Abstract

  Gold plasmonic nanostructures with several different adhesion layers have been studied with monochromated electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and with surface enhanced Raman spectroscopy (SERS). Compared to samples with no adhesion layer, those with 2nm of Cr or Ti show broadened, lower intensity plasmon peaks as measured with EELS. This broadening is observed in both optically active ("bright") and inactive ("dark") plasmon modes. When the former are probed with SERS, the signal enhancement factor is lower for samples with Cr or Ti, another indication of reduced plasmon resonance. This work illustrates the capability of STEM-EELS to provide direct near-field measurement of changes in plasmon excitation probability with nano-scale spatial resolution. Additionally, it demonstrates that applications which require high SERS enhancement, such as biomarker detection and cancer diagnostics, can be improved by avoiding the use of a metallic adhesion layer.

  View details for DOI 10.1021/acsphotonics.6b00525

  View details for Web of Science ID 000394483500011

  View details for PubMedCentralID PMC5604478

• Active flat optics using a guided mode resonance OPTICS LETTERS Kim, S. J., Brongersma, M. L. 2017; 42 (1): 5-8

  Abstract

  Dynamically-controlled flat optics relies on achieving active and effective control over light-matter interaction in ultrathin layers. A variety of metasurface designs have achieved efficient amplitude and phase modulation. Particularly, noteworthy progress has been made with the incorporation of newly emerging electro-optical materials into such metasurfaces, including graphene, phase change materials, and transparent conductive oxides. In this Letter, we demonstrate dynamic light-matter interaction in a silicon-based subwavelength grating that supports a guided mode resonance. By overcoating the grating with indium tin oxide as an electrically tunable material, its reflectance can be tuned from 4% to 86%. Guided mode resonances naturally afford higher optical quality factors than the optical antennas used in the construction of metasurfaces. As such, they facilitate more effective control over the flow of light within the same layer thickness.

  View details for DOI 10.1364/OL.42.000005

  View details for Web of Science ID 000391396800003

  View details for PubMedID 28059210

• Subwavelength Angle Sensing Photodetector Yi, S., Zhou, M., Yu, Z., Fan, P., Lin, D., Fan, S., Brongersma, M., IEEE IEEE. 2017

  View details for Web of Science ID 000427296202462

• Shared-aperture multitasking Pancharatnam-Berry phase dielectric nanoantenna array Maguid, E., Yulevich, I., Yannai, M., Kleiner, V., Brongersma, M. L., Hasman, E., IEEE IEEE. 2017

  View details for Web of Science ID 000427296200495

• All-Silica Multifunctional Beam Information Detector without Destroying Original Wave Fronts Li, Q., Dong, F., Wang, B., Chu, W., Gong, Q., Brongersma, M. L., Li, Y., IEEE IEEE. 2017

  View details for Web of Science ID 000427296200464

• Spin-Controlled Multifunctional Metasurfaces Maguid, E., Yulevich, I., Yannai, M., Kleiner, V., Brongersma, M. L., Hasman, E., IEEE IEEE. 2017

  View details for Web of Science ID 000432564600879

• Dynamic Reflection Phase and Polarization Control in Metasurfaces NANO LETTERS Park, J., Kang, J., Kim, S. J., Liu, X., Brongersma, M. L. 2017; 17 (1): 407-413

  Abstract

  Optical metasurfaces are two-dimensional optical elements composed of dense arrays of subwavelength optical antennas and afford on-demand manipulation of the basic properties of light waves. Following the pioneering works on active metasurfaces capable of modulating wave amplitude, there is now a growing interest to dynamically control other fundamental properties of light. Here, we present metasurfaces that facilitate electrical tuning of the reflection phase and polarization properties. To realize these devices, we leverage the properties of actively controlled plasmonic antennas and fundamental insights provided by coupled mode theory. Indium-tin-oxide is embedded into gap-plasmon resonator-antennas as it offers electrically tunable optical properties. By judiciously controlling the resonant properties of the antennas from under- to overcoupling regimes, we experimentally demonstrate tuning of the reflection phase over 180°. This work opens up new design strategies for active metasurfaces for displacement measurements and tunable waveplates.

  View details for DOI 10.1021/acs.nanolett.6b04378

  View details for Web of Science ID 000392036600058

  View details for PubMedID 27936784

• Fabry-Perot description for Mie resonances of rectangular dielectric nanowire optical resonators OPTICS EXPRESS Landreman, P. E., Chalabi, H., Park, J., Brongersma, M. L. 2016; 24 (26): 29761-29773

  Abstract

  We show that a dielectric nanowire (NW) with a rectangular cross section can effectively be modeled as a Fabry-Perot cavity formed by truncating a dielectric slab waveguide. By calculating the mode indices of the supported waveguide modes and the reflection phase pickup of the guided waves from the end facets, we can numerically predict the spectral locations of optical, Mie-like resonances for such NWs. This type of analysis must be performed twice in order to account for all resonances of these structures, corresponding to light propagating in the vertical or horizontal directions. The model shows excellent agreement with full-field simulations. We show how the refractive index of both the NW itself and neighboring materials and substrates impact the resonant properties. Our results can aid the development of NW-based optoelectronic devices, for which rectangular cross sections are much simpler to fabricate using top-down fabrication procedures.

  View details for DOI 10.1364/OE.24.029760

  View details for Web of Science ID 000390809100050

• Electron energy-loss spectroscopy of branched gap plasmon resonators NATURE COMMUNICATIONS Raza, S., Esfandyarpour, M., Koh, A. L., Mortensen, N. A., Brongersma, M. L., Bozhevolnyi, S. I. 2016; 7

  Abstract

  The miniaturization of integrated optical circuits below the diffraction limit for high-speed manipulation of information is one of the cornerstones in plasmonics research. By coupling to surface plasmons supported on nanostructured metallic surfaces, light can be confined to the nanoscale, enabling the potential interface to electronic circuits. In particular, gap surface plasmons propagating in an air gap sandwiched between metal layers have shown extraordinary mode confinement with significant propagation length. In this work, we unveil the optical properties of gap surface plasmons in silver nanoslot structures with widths of only 25 nm. We fabricate linear, branched and cross-shaped nanoslot waveguide components, which all support resonances due to interference of counter-propagating gap plasmons. By exploiting the superior spatial resolution of a scanning transmission electron microscope combined with electron energy-loss spectroscopy, we experimentally show the propagation, bending and splitting of slot gap plasmons.

  View details for DOI 10.1038/ncomms13790

  View details for Web of Science ID 000390315900001

  View details for PubMedID 27982030

  View details for PubMedCentralID PMC5171719

• Plasmonic Photodetectors, Photovoltaics, and Hot-Electron Devices PROCEEDINGS OF THE IEEE Brongersma, M. L. 2016; 104 (12): 2349-2361

  View details for DOI 10.1109/JPROC.2016.2592946

  View details for Web of Science ID 000389326200008

• Photonic Multitasking Interleaved Si Nanoantenna Phased Array NANO LETTERS Lin, D., Holsteen, A. L., Maguid, E., Wetzstein, G., Kik, P. G., Hasman, E., Brongersma, M. L. 2016; 16 (12): 7671-7676

  Abstract

  Metasurfaces provide unprecedented control over light propagation by imparting local, space-variant phase changes on an incident electromagnetic wave. They can improve the performance of conventional optical elements and facilitate the creation of optical components with new functionalities and form factors. Here, we build on knowledge from shared aperture phased array antennas and Si-based gradient metasurfaces to realize various multifunctional metasurfaces capable of achieving multiple distinct functions within a single surface region. As a key point, we demonstrate that interleaving multiple optical elements can be accomplished without reducing the aperture of each subelement. Multifunctional optical elements constructed from Si-based gradient metasurface are realized, including axial and lateral multifocus geometric phase metasurface lenses. We further demonstrate multiwavelength color imaging with a high spatial resolution. Finally, optical imaging functionality with simultaneous color separation has been obtained by using multifunctional metasurfaces, which opens up new opportunities for the field of advanced imaging and display.

  View details for DOI 10.1021/acs.nanolett.6b03505

  View details for PubMedID 27960478

• Porous Silicon Gradient Refractive Index Micro-Optics NANO LETTERS Krueger, N. A., Holsteen, A. L., Kang, S., Ocier, C. R., Zhou, W., Mensing, G., Rogers, J. A., Brongersma, M. L., Braun, P. V. 2016; 16 (12): 7402-7407

  Abstract

  The emergence and growth of transformation optics over the past decade has revitalized interest in how a gradient refractive index (GRIN) can be used to control light propagation. Two-dimensional demonstrations with lithographically defined silicon (Si) have displayed the power of GRIN optics and also represent a promising opportunity for integrating compact optical elements within Si photonic integrated circuits. Here, we demonstrate the fabrication of three-dimensional Si-based GRIN micro-optics through the shape-defined formation of porous Si (PSi). Conventional microfabrication creates Si square microcolumns (SMCs) that can be electrochemically etched into PSi elements with nanoscale porosity along the shape-defined etching pathway, which imparts the geometry with structural birefringence. Free-space characterization of the transmitted intensity distribution through a homogeneously etched PSi SMC exhibits polarization splitting behavior resembling that of dielectric metasurfaces that require considerably more laborious fabrication. Coupled birefringence/GRIN effects are studied by way of PSi SMCs etched with a linear (increasing from edge to center) GRIN profile. The transmitted intensity distribution shows polarization-selective focusing behavior with one polarization focused to a diffraction-limited spot and the orthogonal polarization focused into two laterally displaced foci. Optical thickness-based analysis readily predicts the experimentally observed phenomena, which strongly match finite-element electromagnetic simulations.

  View details for DOI 10.1021/acs.nanolett.6b02939

  View details for Web of Science ID 000389963200014

  View details for PubMedID 27797522

• Optically resonant dielectric nanostructures SCIENCE Kuznetsov, A. I., Miroshnichenko, A. E., Brongersma, M. L., Kivshar, Y. S., Luk'yanchuk, B. 2016; 354 (6314): 846-?

  Abstract

  Rapid progress in nanophotonics is driven by the ability of optically resonant nanostructures to enhance near-field effects controlling far-field scattering through intermodal interference. A majority of such effects are usually associated with plasmonic nanostructures. Recently, a new branch of nanophotonics has emerged that seeks to manipulate the strong, optically induced electric and magnetic Mie resonances in dielectric nanoparticles with high refractive index. In the design of optical nanoantennas and metasurfaces, dielectric nanoparticles offer the opportunity for reducing dissipative losses and achieving large resonant enhancement of both electric and magnetic fields. We review this rapidly developing field and demonstrate that the magnetic response of dielectric nanostructures can lead to novel physical effects and applications.

  View details for DOI 10.1126/science.aag2472

  View details for Web of Science ID 000388531900030

  View details for PubMedID 27856851

• Focused thermal emission from a nanostructured SiC surface PHYSICAL REVIEW B Chalabi, H., Alu, A., Brongersma, M. L. 2016; 94 (9)

  View details for DOI 10.1103/PhysRevB.94.094307

  View details for Web of Science ID 000383861500001

• Picosecond Electric-Field-Induced Threshold Switching in Phase-Change Materials. Physical review letters Zalden, P., Shu, M. J., Chen, F., Wu, X., Zhu, Y., Wen, H., Johnston, S., Shen, Z., Landreman, P., Brongersma, M., Fong, S. W., Wong, H. P., Sher, M., Jost, P., Kaes, M., Salinga, M., von Hoegen, A., Wuttig, M., Lindenberg, A. M. 2016; 117 (6): 067601-?

  Abstract

  Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag_{4}In_{3}Sb_{67}Te_{26}. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on subpicosecond time scales-faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.

  View details for DOI 10.1103/PhysRevLett.117.067601

  View details for PubMedID 27541475

• Photonic spin-controlled multifunctional shared-aperture antenna array SCIENCE Maguid, E., Yulevich, I., Veksler, D., Kleiner, V., Brongersma, M. L., Hasman, E. 2016; 352 (6290): 1202-1206

  Abstract

  The shared-aperture phased antenna array developed in the field of radar applications is a promising approach for increased functionality in photonics. The alliance between the shared-aperture concepts and the geometric phase phenomenon arising from spin-orbit interaction provides a route to implement photonic spin-control multifunctional metasurfaces. We adopted a thinning technique within the shared-aperture synthesis and investigated interleaved sparse nanoantenna matrices and the spin-enabled asymmetric harmonic response to achieve helicity-controlled multiple structured wavefronts such as vortex beams carrying orbital angular momentum. We used multiplexed geometric phase profiles to simultaneously measure spectrum characteristics and the polarization state of light, enabling integrated on-chip spectropolarimetric analysis. The shared-aperture metasurface platform opens a pathway to novel types of nanophotonic functionality.

  View details for DOI 10.1126/science.aaf3417

  View details for Web of Science ID 000377045700038

  View details for PubMedID 27103668

• Superabsorbing, Artificial Metal Films Constructed from Semiconductor Nanoantennas NANO LETTERS Kim, S. J., Park, J., Esfandyarpour, M., Pecora, E. F., Kik, P. G., Brongersma, M. L. 2016; 16 (6): 3801-3808

  Abstract

  In 1934, Wilhelm Woltersdorff demonstrated that the absorption of light in an ultrathin, freestanding film is fundamentally limited to 50%. He concluded that reaching this limit would require a film with a real-valued sheet resistance that is exactly equal to R = η/2 ≈ 188.5Ω/□, where [Formula: see text] is the impedance of free space. This condition can be closely approximated over a wide frequency range in metals that feature a large imaginary relative permittivity εr″, that is, a real-valued conductivity σ = ε0εr″ω. A thin, continuous sheet of semiconductor material does not facilitate such strong absorption as its complex-valued permittivity with both large real and imaginary components preclude effective impedance matching. In this work, we show how a semiconductor metafilm constructed from optically resonant semiconductor nanostructures can be created whose optical response mimics that of a metallic sheet. For this reason, the fundamental absorption limit mentioned above can also be reached with semiconductor materials, opening up new opportunities for the design of ultrathin optoelectronic and light harvesting devices.

  View details for DOI 10.1021/acs.nanolett.6b01198

  View details for Web of Science ID 000377642700057

  View details for PubMedID 27149008

• Combined electron energy-loss and cathodoluminescence spectroscopy on individual and composite plasmonic nanostructures PHYSICAL REVIEW B Coenen, T., Schoen, D. T., Brenny, B. J., Polman, A., Brongersma, M. L. 2016; 93 (19)

  View details for DOI 10.1103/PhysRevB.93.195429

  View details for Web of Science ID 000376249800007

• Probing the electrical switching of a memristive optical antenna by STEM EELS. Nature communications Schoen, D. T., Holsteen, A. L., Brongersma, M. L. 2016; 7: 12162-?

  Abstract

  The scaling of active photonic devices to deep-submicron length scales has been hampered by the fundamental diffraction limit and the absence of materials with sufficiently strong electro-optic effects. Plasmonics is providing new opportunities to circumvent this challenge. Here we provide evidence for a solid-state electro-optical switching mechanism that can operate in the visible spectral range with an active volume of less than (5 nm)(3) or ∼10(-6) λ(3), comparable to the size of the smallest electronic components. The switching mechanism relies on electrochemically displacing metal atoms inside the nanometre-scale gap to electrically connect two crossed metallic wires forming a cross-point junction. These junctions afford extreme light concentration and display singular optical behaviour upon formation of a conductive channel. The active tuning of plasmonic antennas attached to such junctions is analysed using a combination of electrical and optical measurements as well as electron energy loss spectroscopy in a scanning transmission electron microscope.

  View details for DOI 10.1038/ncomms12162

  View details for PubMedID 27412052

  View details for PubMedCentralID PMC4947179

• Engineering optical properties of semiconductor metafilm superabsorbers Kim, S., Fan, P., Kang, J., Brongersma, M. L., Boardman, A. D., Johnson, N. P., MacDonald, K. F., Ozbay, E. SPIE-INT SOC OPTICAL ENGINEERING. 2016

  View details for DOI 10.1117/12.2231164

  View details for Web of Science ID 000381076600023

• Backward Phase-Matching in Negative-Index Materials Lan, S., Kang, L., Schoen, D. T., Rodrigues, S. P., Cui, Y., Brongersma, M. L., Cai, W., IEEE IEEE. 2016

  View details for Web of Science ID 000391286401133

• Photonic Spin-Controlled Multifunctional Shared-Aperture Antenna Array Maguid, E., Yulevich, I., Veksler, D., Kleiner, V., Brongersma, M. L., Hasman, E., IEEE IEEE. 2016: 200–201

  View details for Web of Science ID 000406880100098

• Tensile-Strained GeSn Photodetectors with Conformal Nitride Stressor Morea, M., Zang, K., Fenrich, C. S., Huang, Y., Chung, H., Curto, A. G., Huo, Y., Kamins, T. I., Brongersma, M. L., Harris, J. S., IEEE IEEE. 2016: 21–22

  View details for Web of Science ID 000386968000012

• Electrically Tunable Epsilon-Near-Zero (ENZ) Metafilm Absorbers SCIENTIFIC REPORTS Park, J., Kang, J., Liu, X., Brongersma, M. L. 2015; 5

  Abstract

  Enhancing and spectrally controlling light absorption is of great practical and fundamental importance. In optoelectronic devices consisting of layered semiconductors and metals, absorption has traditionally been manipulated with the help of Fabry-Pérot resonances. Even further control over the spectral light absorption properties of thin films has been achieved by patterning them into dense arrays of subwavelength resonant structures to form metafilms. As the next logical step, we demonstrate electrical control over light absorption in metafilms constructed from dense arrays of actively tunable plasmonic cavities. This control is achieved by embedding indium tin oxide (ITO) into these cavities. ITO affords significant tuning of its optical properties by means of electrically-induced carrier depletion and accumulation. We demonstrate that particularly large changes in the reflectance from such metafilms (up to 15% P) can be achieved by operating the ITO in the epsilon-near-zero (ENZ) frequency regime where its electrical permittivity changes sign from negative to positive values.

  View details for DOI 10.1038/srep15754

  View details for Web of Science ID 000364288500001

  View details for PubMedID 26549615

  View details for PubMedCentralID PMC4637893

• Nanoscale Spatial Coherent Control over the Modal Excitation of a Coupled Plasmonic Resonator System NANO LETTERS Coenen, T., Schoen, D. T., Mann, S. A., Rodriguez, S. R., Brenny, B. J., Polman, A., Brongersma, M. L. 2015; 15 (11): 7666-7670

  Abstract

  We demonstrate coherent control over the optical response of a coupled plasmonic resonator by high-energy electron beam excitation. We spatially control the position of an electron beam on a gold dolmen and record the cathodoluminescence and electron energy loss spectra. By selective coherent excitation of the dolmen elements in the near field, we are able to manipulate modal amplitudes of bonding and antibonding eigenmodes. We employ a combination of CL and EELS to gain detailed insight in the power dissipation of these modes at the nanoscale as CL selectively probes the radiative response and EELS probes the combined effect of Ohmic dissipation and radiation.

  View details for DOI 10.1021/acs.nanolett.5b03614

  View details for Web of Science ID 000364725400074

  View details for PubMedID 26457569

• Li Intercalation in MoS2: In Situ Observation of Its Dynamics and Tuning Optical and Electrical Properties NANO LETTERS Xiong, F., Wang, H., Liu, X., Sun, J., Brongersma, M., Pop, E., Cui, Y. 2015; 15 (10): 6777-6784

  Abstract

  Two-dimensional layered materials like MoS2 have shown promise for nanoelectronics and energy storage, both as monolayers and as bulk van der Waals crystals with tunable properties. Here we present a platform to tune the physical and chemical properties of nanoscale MoS2 by electrochemically inserting a foreign species (Li(+) ions) into their interlayer spacing. We discover substantial enhancement of light transmission (up to 90% in 4 nm thick lithiated MoS2) and electrical conductivity (more than 200×) in ultrathin (∼2-50 nm) MoS2 nanosheets after Li intercalation due to changes in band structure that reduce absorption upon intercalation and the injection of large amounts of free carriers. We also capture the first in situ optical observations of Li intercalation in MoS2 nanosheets, shedding light on the dynamics of the intercalation process and the associated spatial inhomogeneity and cycling-induced structural defects.

  View details for DOI 10.1021/acs.nanolett.5b02619

  View details for PubMedID 26352295

• Backward phase-matching for nonlinear optical generation in negative-index materials NATURE MATERIALS Lan, S., Kang, L., Schoen, D. T., Rodrigues, S. P., Cui, Y., Brongersma, M. L., Cai, W. 2015; 14 (8): 807-?

  Abstract

  Metamaterials have enabled the realization of unconventional electromagnetic properties not found in nature, which provokes us to rethink the established rules of optics in both the linear and nonlinear regimes. One of the most intriguing phenomena in nonlinear metamaterials is 'backward phase-matching', which describes counter-propagating fundamental and harmonic waves in a negative-index medium. Predicted nearly a decade ago, this process is still awaiting a definitive experimental confirmation at optical frequencies. Here, we report optical measurements showing backward phase-matching by exploiting two distinct modes in a nonlinear plasmonic waveguide, where the real parts of the mode refractive indices are 3.4 and -3.4 for the fundamental and the harmonic waves respectively. The observed peak conversion efficiency at the excitation wavelength of ∼780 nm indicates the fulfilment of the phase-matching condition of k(2ω) = 2k(ω) and n(2ω) = -n(ω), where the coherent harmonic wave emerges along a direction opposite to that of the incoming fundamental light.

  View details for DOI 10.1038/NMAT4324

  View details for Web of Science ID 000358530100023

• Backward phase-matching for nonlinear optical generation in negative-index materials. Nature materials Lan, S., Kang, L., Schoen, D. T., Rodrigues, S. P., Cui, Y., Brongersma, M. L., Cai, W. 2015; 14 (8): 807-11

  Abstract

  Metamaterials have enabled the realization of unconventional electromagnetic properties not found in nature, which provokes us to rethink the established rules of optics in both the linear and nonlinear regimes. One of the most intriguing phenomena in nonlinear metamaterials is 'backward phase-matching', which describes counter-propagating fundamental and harmonic waves in a negative-index medium. Predicted nearly a decade ago, this process is still awaiting a definitive experimental confirmation at optical frequencies. Here, we report optical measurements showing backward phase-matching by exploiting two distinct modes in a nonlinear plasmonic waveguide, where the real parts of the mode refractive indices are 3.4 and -3.4 for the fundamental and the harmonic waves respectively. The observed peak conversion efficiency at the excitation wavelength of ∼780 nm indicates the fulfilment of the phase-matching condition of k(2ω) = 2k(ω) and n(2ω) = -n(ω), where the coherent harmonic wave emerges along a direction opposite to that of the incoming fundamental light.

  View details for DOI 10.1038/nmat4324

  View details for PubMedID 26076305

• Gap Plasmon Resonance in a Suspended Plasmonic Nanowire Coupled to a Metallic Substrate NANO LETTERS Miyata, M., Holsteen, A., Nagasaki, Y., Brongersma, M. L., Takahara, J. 2015; 15 (8): 5609-5616

  Abstract

  We present an experimental demonstration of nanoscale gap plasmon resonators that consist of an individual suspended plasmonic nanowire (NW) over a metallic substrate. Our study demonstrates that the NW supports strong gap plasmon resonances of various gap sizes including single-nanometer-scale gaps. The obtained resonance features agree well with intuitive resonance models for near- and far-field regimes. We also illustrate that our suspended NW geometry is capable of constructing plasmonic coupled systems dominated by quasi-electrostatics.

  View details for DOI 10.1021/acs.nanolett.5b02307

  View details for Web of Science ID 000359613700115

  View details for PubMedID 26192214

• Ultrafast Carrier Dynamics of a Photo-Excited Germanium Nanowire-Air Metamaterial ACS PHOTONICS Li, Y., Clady, R., Marshall, A. F., Park, J., Thombare, S. V., Chan, G., Schmidt, T. W., Brongersma, M. L., McIntyre, P. C. 2015; 2 (8): 1091-1098

  View details for DOI 10.1021/acsphotonics.5b00147

  View details for Web of Science ID 000359967400014

• Polarization-sensitive broadband photodetector using a black phosphorus vertical p-n junction NATURE NANOTECHNOLOGY Yuan, H., Liu, X., Afshinmanesh, F., Li, W., Xu, G., Sun, J., Lian, B., Curto, A. G., Ye, G., Hikita, Y., Shen, Z., Zhang, S., Chen, X., Brongersma, M., Hwang, H. Y., Cui, Y. 2015; 10 (8): 707-713

  Abstract

  The ability to detect light over a broad spectral range is central to practical optoelectronic applications and has been successfully demonstrated with photodetectors of two-dimensional layered crystals such as graphene and MoS2. However, polarization sensitivity within such a photodetector remains elusive. Here, we demonstrate a broadband photodetector using a layered black phosphorus transistor that is polarization-sensitive over a bandwidth from ∼400 nm to 3,750 nm. The polarization sensitivity is due to the strong intrinsic linear dichroism, which arises from the in-plane optical anisotropy of this material. In this transistor geometry, a perpendicular built-in electric field induced by gating can spatially separate the photogenerated electrons and holes in the channel, effectively reducing their recombination rate and thus enhancing the performance for linear dichroism photodetection. The use of anisotropic layered black phosphorus in polarization-sensitive photodetection might provide new functionalities in novel optical and optoelectronic device applications.

  View details for DOI 10.1038/NNANO.2015.112

  View details for PubMedID 26030655

• Tuning Optical Absorption in an Ultrathin Lossy Film by Use of a Metallic Metamaterial Mirror IEEE PHOTONICS TECHNOLOGY LETTERS Park, J., Kang, J., Kim, S. J., Hasman, E., Brongersma, M. L. 2015; 27 (15): 1617-1620

  View details for DOI 10.1109/LPT.2015.2432756

  View details for Web of Science ID 000357830000011

• Creating semiconductor metafilms with designer absorption spectra NATURE COMMUNICATIONS Kim, S. J., Fan, P., Kang, J., Brongersma, M. L. 2015; 6

  Abstract

  The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.

  View details for DOI 10.1038/ncomms8591

  View details for Web of Science ID 000358855900004

  View details for PubMedCentralID PMC4518292

• Bandgap-customizable germanium using lithographically determined biaxial tensile strain for silicon-compatible optoelectronics OPTICS EXPRESS Sukhdeo, D. S., Nam, D., Kang, J., Brongersma, M. L., Saraswat, K. C. 2015; 23 (13): 16740-16749

  Abstract

  Strain engineering has proven to be vital for germanium-based photonics, in particular light emission. However, applying a large permanent biaxial tensile strain to germanium has been a challenge. We present a simple, CMOS-compatible technique to conveniently induce a large, spatially homogenous strain in circular structures patterned within germanium nanomembranes. Our technique works by concentrating and amplifying a pre-existing small strain into a circular region. Biaxial tensile strains as large as 1.11% are observed by Raman spectroscopy and are further confirmed by photoluminescence measurements, which show enhanced and redshifted light emission from the strained germanium. Our technique allows the amount of biaxial strain to be customized lithographically, allowing the bandgaps of different germanium structures to be independently customized in a single mask process.

  View details for DOI 10.1364/OE.23.016740

  View details for Web of Science ID 000358543300026

• Monolithic integration of germanium-on-insulator p-i-n photodetector on silicon OPTICS EXPRESS Nam, J. H., Afshinmanesh, F., Nam, D., Jung, W. S., Kamins, T. I., Brongersma, M. L., Saraswat, K. C. 2015; 23 (12): 15816-15823

  Abstract

  A germanium-on-insulator (GOI) p-i-n photodetector, monolithically integrated on a silicon (Si) substrate, is demonstrated. GOI is formed by lateral-overgrowth (LAT-OVG) of Ge on silicon dioxide (SiO(2)) through windows etched in SiO(2) on Si. The photodetector shows excellent diode characteristics with high on/off ratio (6 × 10(4)), low dark current, and flat reverse current-voltage (I-V) characteristics. Enhanced light absorption up to 1550 nm is observed due to the residual biaxial tensile strain induced during the epitaxial growth of Ge caused by cooling after the deposition. This truly Si-compatible Ge photodetector using monolithic integration enables new opportunities for high-performance GOI based photonic devices on Si platform.

  View details for DOI 10.1364/OE.23.015816

  View details for Web of Science ID 000356902500068

• Effect of shape in near-field thermal transfer for periodic structures PHYSICAL REVIEW B Chalabi, H., Hasman, E., Brongersma, M. L. 2015; 91 (17)

  View details for DOI 10.1103/PhysRevB.91.174304

  View details for Web of Science ID 000355088000004

• Condition for unity absorption in an ultrathin and highly lossy film in a Gires-Tournois interferometer configuration OPTICS LETTERS Park, J., Kim, S. J., Brongersma, M. L. 2015; 40 (9): 1960-1963

  Abstract

  We present a condition for unity absorption for a Gires-Tournois interferometer configuration constructed from an ultrathin and highly lossy film on top of metallic mirror. From the impedance matching condition in the transmission line theory, we identify a solution space for the required complex refractive index of the lossy film in various film thickness and dielectric constants of the metallic mirror. It is shown that strong absorption requires the imaginary part of the refractive index of the ultrathin lossy film be larger than 0.64, and the physical origin of this condition is elucidated. The proposed method is useful in identifying candidate semiconductor materials that can be used as the lossy film in a unity-absorption Gires-Tournois interferometer configuration and designing the thickness of this film to maximize absorption.

  View details for DOI 10.1364/OL.40.001960

  View details for Web of Science ID 000353924600020

  View details for PubMedID 25927758

• Lateral overgrowth of germanium for monolithic integration of germanium-on-insulator on silicon JOURNAL OF CRYSTAL GROWTH Nam, J. H., Alkis, S., Nam, D., Afshinmanesh, F., Shim, J., Park, J., Brongersma, M., Okyay, A. K., Kamins, T. I., Saraswat, K. 2015; 416: 21-27

  View details for DOI 10.1016/j.jcrysgro.2014.11.004

  View details for Web of Science ID 000350748000005

• Electrically tunable coherent optical absorption in graphene with ion gel. Nano letters Thareja, V., Kang, J., Yuan, H., Milaninia, K. M., Hwang, H. Y., Cui, Y., Kik, P. G., Brongersma, M. L. 2015; 15 (3): 1570-1576

  Abstract

  We demonstrate electrical control over coherent optical absorption in a graphene-based Salisbury screen consisting of a single layer of graphene placed in close proximity to a gold back reflector. The screen was designed to enhance light absorption at a target wavelength of 3.2 μm by using a 600 nm-thick, nonabsorbing silica spacer layer. An ionic gel layer placed on top of the screen was used to electrically gate the charge density in the graphene layer. Spectroscopic reflectance measurements were performed in situ as a function of gate bias. The changes in the reflectance spectra were analyzed using a Fresnel based transfer matrix model in which graphene was treated as an infinitesimally thin sheet with a conductivity given by the Kubo formula. The analysis reveals that a careful choice of the ionic gel layer thickness can lead to optical absorption enhancements of up to 5.5 times for the Salisbury screen compared to a suspended sheet of graphene. In addition to these absorption enhancements, we demonstrate very large electrically induced changes in the optical absorption of graphene of ∼3.3% per volt, the highest attained so far in a device that features an atomically thick active layer. This is attributable in part to the more effective gating achieved with the ion gel over the conventional dielectric back gates and partially by achieving a desirable coherent absorption effect linked to the presence of the thin ion gel that boosts the absorption by 40%.

  View details for DOI 10.1021/nl503431d

  View details for PubMedID 25671369

• Shape-Dependent Light Scattering Properties of Subwavelength Silicon Nanoblocks NANO LETTERS Ee, H., Kang, J., Brongersma, M. L., Seo, M. 2015; 15 (3): 1759-1765

  Abstract

  We explore the shape-dependent light scattering properties of silicon (Si) nanoblocks and their physical origin. These high-refractive-index nanostructures are easily fabricated using planar fabrication technologies and support strong, leaky-mode resonances that enable light manipulation beyond the optical diffraction limit. Dark-field microscopy and a numerical modal analysis show that the nanoblocks can be viewed as truncated Si waveguides, and the waveguide dispersion strongly controls the resonant properties. This explains why the lowest-order transverse magnetic (TM01) mode resonance can be widely tuned over the entire visible wavelength range depending on the nanoblock length, whereas the wavelength-scale TM11 mode resonance does not change greatly. For sufficiently short lengths, the TM01 and TM11 modes can be made to spectrally overlap, and a substantial scattering efficiency, which is defined as the ratio of the scattering cross section to the physical cross section of the nanoblock, of ∼9.95, approaching the theoretical lowest-order single-channel scattering limit, is achievable. Control over the subwavelength-scale leaky-mode resonance allows Si nanoblocks to generate vivid structural color, manipulate forward and backward scattering, and act as excellent photonic artificial atoms for metasurfaces.

  View details for DOI 10.1021/nl504442v

  View details for Web of Science ID 000351188000048

  View details for PubMedID 25668601

• Probing Complex Reflection Coefficients in One-Dimensional Surface Plasmon Polariton Waveguides and Cavities Using STEM EELS. Nano letters Schoen, D. T., Atre, A. C., García-Etxarri, A., Dionne, J. A., Brongersma, M. L. 2015; 15 (1): 120-126

  Abstract

  The resonant properties of a plasmonic cavity are determined by the size of the cavity, the surface plasmon polariton (SPP) dispersion relationship, and the complex reflection coefficients of the cavity boundaries. In small wavelength-scale cavities, the phase propagation due to reflections from the cavity walls is of a similar magnitude to propagation due to traversing the cavity. Until now, this reflection phase has been inferred from measurements of the resonant frequencies of a cavity of known dispersion and length. In this work, we present a method for measuring the complex reflection coefficients of a truncation in a 1D surface plasmon waveguide using electron energy loss spectroscopy in the scanning transmission electron microscope (STEM EELS) and show that this insight can be used to engineer custom cavities with engineered reflecting boundaries, whose resonant wavelengths and internal mode density profiles can be analytically predicted given knowledge of the cavity dimensions and complex reflection coefficients of the boundaries.

  View details for DOI 10.1021/nl503179j

  View details for PubMedID 25545292

• Near-field radiative thermal transfer between a nanostructured periodic material and a planar substrate PHYSICAL REVIEW B Chalabi, H., Hasman, E., Brongersma, M. L. 2015; 91 (1)

  View details for DOI 10.1103/PhysRevB.91.014302

  View details for Web of Science ID 000348702700001

• Significant enhancement of infrared photodetector sensitivity using a semiconducting single-walled carbon nanotube/c60 phototransistor. Advanced materials Park, S., Kim, S. J., Nam, J. H., Pitner, G., Lee, T. H., Ayzner, A. L., Wang, H., Fong, S. W., Vosgueritchian, M., Park, Y. J., Brongersma, M. L., Bao, Z. 2015; 27 (4): 759-765

  Abstract

  A highly sensitive single-walled carbon nanotube/C60 -based infrared photo-transistor is fabricated with a responsivity of 97.5 A W(-1) and detectivity of 1.17 × 10(9) Jones at 1 kHz under a source/drain bias of -0.5 V. The much improved performance is enabled by this unique device architecture that enables a high photoconductive gain of ≈10(4) with a response time of several milliseconds.

  View details for DOI 10.1002/adma.201404544

  View details for PubMedID 25607919

• Device Applications of Semiconductor Nanoantennas and Metafilms Brongersma, M. L., Engheta, N., Noginov, M. A., Zheludev, N. I. SPIE-INT SOC OPTICAL ENGINEERING. 2015

  View details for DOI 10.1117/12.2194906

  View details for Web of Science ID 000368010300003

• Device applications of metafilms and metasurfaces Brongersma, M. L., Engheta, N., Noginov, M. A., Zheludev, N. I. SPIE-INT SOC OPTICAL ENGINEERING. 2015

  View details for DOI 10.1117/12.2189965

  View details for Web of Science ID 000368010300048

• Creating semiconductor metafilms with designer absorption spectra. Nature communications Kim, S. J., Fan, P., Kang, J., Brongersma, M. L. 2015; 6: 7591-?

  Abstract

  The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.

  View details for DOI 10.1038/ncomms8591

  View details for PubMedID 26184335

  View details for PubMedCentralID PMC4518292

• Introductory lecture: nanoplasmonics FARADAY DISCUSSIONS Brongersma, M. L. 2015; 178: 9-36

  Abstract

  Nanoplasmonics or nanoscale metal-based optics is a field of science and technology with a tremendously rich and colourful history. Starting with the early works of Michael Faraday on gold nanocolloids and optically-thin gold leaf, researchers have been fascinated by the unusual optical properties displayed by metallic nanostructures. We now can enjoy selecting from over 10 000 publications every year on the topic of plasmonics and the number of publications has been doubling about every three years since 1990. This impressive productivity can be attributed to the significant growth of the scientific community as plasmonics has spread into a myriad of new directions. With 2015 being the International Year of Light, it seems like a perfect moment to review some of the most notable accomplishments in plasmonics to date and to project where the field may be moving next. After discussing some of the major historical developments in the field, this article will analyse how the most successful plasmonics applications are capitalizing on five key strengths of metallic nanostructures. This Introductory Lecture will conclude with a brief look into the future.

  View details for DOI 10.1039/c5fd90020d

  View details for Web of Science ID 000354962300001

  View details for PubMedID 25968246

• Plasmon-induced hot carrier science and technology NATURE NANOTECHNOLOGY Brongersma, M. L., Halas, N. J., Nordlander, P. 2015; 10 (1): 25-34

  Abstract

  The discovery of the photoelectric effect by Heinrich Hertz in 1887 set the foundation for over 125 years of hot carrier science and technology. In the early 1900s it played a critical role in the development of quantum mechanics, but even today the unique properties of these energetic, hot carriers offer new and exciting opportunities for fundamental research and applications. Measurement of the kinetic energy and momentum of photoejected hot electrons can provide valuable information on the electronic structure of materials. The heat generated by hot carriers can be harvested to drive a wide range of physical and chemical processes. Their kinetic energy can be used to harvest solar energy or create sensitive photodetectors and spectrometers. Photoejected charges can also be used to electrically dope two-dimensional materials. Plasmon excitations in metallic nanostructures can be engineered to enhance and provide valuable control over the emission of hot carriers. This Review discusses recent advances in the understanding and application of plasmon-induced hot carrier generation and highlights some of the exciting new directions for the field.

  View details for DOI 10.1038/NNANO.2014.311

  View details for Web of Science ID 000347405800015

  View details for PubMedID 25559968

• An ab-initio coupled mode theory for near field radiative thermal transfer OPTICS EXPRESS Chalabi, H., Hasman, E., Brongersma, M. L. 2014; 22 (24): 30032-30046

  Abstract

  We investigate the thermal transfer between finite-thickness planar slabs which support surface phonon polariton modes (SPhPs). The thickness-dependent dispersion of SPhPs in such layered materials provides a unique opportunity to manipulate and enhance the near field thermal transfer. The key accomplishment of this paper is the development of an ab-initio coupled mode theory that accurately describes all of its thermal transfer properties. We illustrate how the coupled mode parameters can be obtained in a direct fashion from the dispersion relation of the relevant modes of the system. This is illustrated for the specific case of a semi-infinite SiC substrate placed in close proximity to a thin slab of SiC. This is a system that exhibits rich physics in terms of its thermal transfer properties, despite the seemingly simple geometry. This includes a universal scaling behavior of the thermal conductance with the slab thickness and spacing. The work highlights and further increases the value of coupled mode theories in rapidly calculating and intuitively understanding near-field transfer.

  View details for DOI 10.1364/OE.22.030032

  View details for Web of Science ID 000345770500071

• Quantification and impact of nonparabolicity of the conduction band of indium tin oxide on its plasmonic properties APPLIED PHYSICS LETTERS Liu, X., Park, J., Kang, J., Yuan, H., Cui, Y., Hwang, H. Y., Brongersma, M. L. 2014; 105 (18)

  View details for DOI 10.1063/1.4900936

  View details for Web of Science ID 000345000000017

• Observation of improved minority carrier lifetimes in high-quality Ge-on-insulator using time-resolved photoluminescence OPTICS LETTERS Nam, D., Kang, J., Brongersma, M. L., Saraswat, K. C. 2014; 39 (21): 6205-6208

  Abstract

  We report improved minority carrier lifetimes in n-type-doped and tensile-strained germanium by measuring direct bandgap photoluminescence from germanium-on-insulator substrates with various levels of defect density. We first describe a method to fabricate a high-quality germanium-on-insulator substrate by employing direct wafer bonding and chemical-mechanical polishing. Raman spectroscopy measurement was performed to assess the purity of the transferred layer on an insulator. Using time-resolved photoluminescence decay measurement, we observe that minority carrier lifetimes can be improved by over a factor of 3 as the defective top interface of our material stack is removed. Our high-quality germanium-on-insulator should be an ideal platform for high-performance, germanium-based photonic devices for on-chip optical interconnects.

  View details for DOI 10.1364/OL.39.006205

  View details for Web of Science ID 000344985900030

• Transparent metallic fractal electrodes for semiconductor devices. Nano letters Afshinmanesh, F., Curto, A. G., Milaninia, K. M., van Hulst, N. F., Brongersma, M. L. 2014; 14 (9): 5068-5074

  Abstract

  Nanostructured metallic films have the potential to replace metal oxide films as transparent electrodes in optoelectronic devices. An ideal transparent electrode should possess a high, broadband, and polarization-independent transmittance. Conventional metallic gratings and grids with wavelength-scale periodicities, however, do not have all of these qualities. Furthermore, the transmission properties of a nanostructured electrode need to be assessed in the actual dielectric environment provided by a device, where a high-index semiconductor layer can reflect a substantial fraction of the incident light. Here we propose nanostructured aluminum electrodes with space-filling fractal geometries as alternatives to gratings and grids and experimentally demonstrate their superior optoelectronic performance through integration with Si photodetectors. As shown by polarization and spectrally resolved photocurrent measurements, devices with fractal electrodes exhibit both a broadband transmission and a flat polarization response that outperforms both square grids and linear gratings. Finally, we show the benefits of adding a thin silicon nitride film to the nanostructured electrodes to further reduce reflection.

  View details for DOI 10.1021/nl501738b

  View details for PubMedID 25140611

• Transparent Metallic Fractal Electrodes for Semiconductor Devices NANO LETTERS Afshinmanesh, F., Curto, A. G., Milaninia, K. M., van Hulst, N. F., Brongersma, M. L. 2014; 14 (9): 5068-5074

  Abstract

  Nanostructured metallic films have the potential to replace metal oxide films as transparent electrodes in optoelectronic devices. An ideal transparent electrode should possess a high, broadband, and polarization-independent transmittance. Conventional metallic gratings and grids with wavelength-scale periodicities, however, do not have all of these qualities. Furthermore, the transmission properties of a nanostructured electrode need to be assessed in the actual dielectric environment provided by a device, where a high-index semiconductor layer can reflect a substantial fraction of the incident light. Here we propose nanostructured aluminum electrodes with space-filling fractal geometries as alternatives to gratings and grids and experimentally demonstrate their superior optoelectronic performance through integration with Si photodetectors. As shown by polarization and spectrally resolved photocurrent measurements, devices with fractal electrodes exhibit both a broadband transmission and a flat polarization response that outperforms both square grids and linear gratings. Finally, we show the benefits of adding a thin silicon nitride film to the nanostructured electrodes to further reduce reflection.

  View details for DOI 10.1021/nl501738b

  View details for Web of Science ID 000341544500022

• Omnidirectional Near-Unity Absorption in an Ultrathin Planar Semiconductor Layer on a Metal Substrate ACS PHOTONICS Park, J., Kang, J., Vasudev, A. P., Schoen, D. T., Kim, H., Hasman, E., Brongersma, M. L. 2014; 1 (9): 812-821

  View details for DOI 10.1021/ph500093d

  View details for Web of Science ID 000342120300010

• Dielectric gradient metasurface optical elements. Science Lin, D., Fan, P., Hasman, E., Brongersma, M. L. 2014; 345 (6194): 298-302

  Abstract

  Gradient metasurfaces are two-dimensional optical elements capable of manipulating light by imparting local, space-variant phase changes on an incident electromagnetic wave. These surfaces have thus far been constructed from nanometallic optical antennas, and high diffraction efficiencies have been limited to operation in reflection mode. We describe the experimental realization and operation of dielectric gradient metasurface optical elements capable of also achieving high efficiencies in transmission mode in the visible spectrum. Ultrathin gratings, lenses, and axicons have been realized by patterning a 100-nanometer-thick Si layer into a dense arrangement of Si nanobeam antennas. The use of semiconductors can broaden the general applicability of gradient metasurfaces, as they offer facile integration with electronics and can be realized by mature semiconductor fabrication technologies.

  View details for DOI 10.1126/science.1253213

  View details for PubMedID 25035488

• Metamaterial mirrors in optoelectronic devices. Nature nanotechnology Esfandyarpour, M., Garnett, E. C., Cui, Y., McGehee, M. D., Brongersma, M. L. 2014; 9 (7): 542-547

  Abstract

  The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror (φ = π) to that of a perfect magnetic mirror (φ = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band.

  View details for DOI 10.1038/nnano.2014.117

  View details for PubMedID 24952475

• Study of Carrier Statistics in Uniaxially Strained Ge for a Low-Threshold Ge Laser IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Nam, D., Sukhdeo, D. S., Gupta, S., Kang, J., Brongersma, M. L., Saraswat, K. C. 2014; 20 (4)

  View details for DOI 10.1109/JSTQE.2013.2293764

  View details for Web of Science ID 000330317900002

• Ultrafast electron and phonon response of oriented and diameter-controlled germanium nanowire arrays. Nano letters Li, Y., Clady, R., Park, J., Thombare, S. V., Schmidt, T. W., Brongersma, M. L., McIntyre, P. C. 2014; 14 (6): 3427-3431

  Abstract

  Carrier and phonon dynamics in dense arrays of aligned, single-crystal Ge nanowires (NWs) of controlled diameter are investigated by ultrafast optical pump-probe measurements, effective medium calculations, and elasticity analysis. Both a pronounced induced absorption and the amplitude and spectral range of Fabry-Perot oscillations observed in the probe signal are predicted for the NW array/air metamaterial by effective medium calculations. Detected temporal oscillations of reflectivity are consistent with excitation of radial breathing mode acoustic phonons by the intense pump pulse.

  View details for DOI 10.1021/nl500953p

  View details for PubMedID 24797453

• Second-Harmonic Generation in GaAs Photonic Crystal Cavities in (111)B and (001) Crystal Orientations ACS PHOTONICS Buckley, S., Radulaski, M., Petykiewicz, J., Lagoudakis, K. G., Kang, J., Brongersma, M., Biermann, K., Vuckovic, J. 2014; 1 (6): 516-523

  View details for DOI 10.1021/ph500054u

  View details for Web of Science ID 000337720300007

• Direct bandgap germanium-on-silicon inferred from 5.7% < 100 > uniaxial tensile strain [Invited] PHOTONICS RESEARCH Sukhdeo, D. S., Nam, D., Kang, J., Brongersma, M. L., Saraswat, K. C. 2014; 2 (3): A8-A13

  View details for DOI 10.1364/PRJ.2.0000A8

  View details for Web of Science ID 000353881100002

• Optical Fano resonance of an individual semiconductor nanostructure NATURE MATERIALS Fan, P., Yu, Z., Fan, S., Brongersma, M. L. 2014; 13 (5): 471-475

  Abstract

  Fano resonances with a characteristic asymmetric line shape can be observed in light scattering, transmission and reflection spectra of resonant optical systems. They result from interference between direct and indirect, resonance-assisted pathways. In the nanophotonics field, Fano effects have been observed in a wide variety of systems, including metallic nanoparticle assemblies, metamaterials and photonic crystals. Their unique properties find extensive use in applications, including optical filtering, polarization selectors, sensing, lasers, modulators and nonlinear optics. We report on the observation of a Fano resonance in a single semiconductor nanostructure, opening up opportunities for their use in active photonic devices. We also show that Fano-resonant semiconductor nanostructures afford the intriguing opportunity to simultaneously measure the far-field scattering response and the near-field energy storage by extracting photogenerated charge. Together they can provide a complete experimental characterization of this type of resonance.

  View details for DOI 10.1038/NMAT3927

  View details for Web of Science ID 000334845600017

  View details for PubMedID 24747781

• Light management for photovoltaics using high-index nanostructures NATURE MATERIALS Brongersma, M. L., Cui, Y., Fan, S. 2014; 13 (5): 451-460

  Abstract

  High-performance photovoltaic cells use semiconductors to convert sunlight into clean electrical power, and transparent dielectrics or conductive oxides as antireflection coatings. A common feature of these materials is their high refractive index. Whereas high-index materials in a planar form tend to produce a strong, undesired reflection of sunlight, high-index nanostructures afford new ways to manipulate light at a subwavelength scale. For example, nanoscale wires, particles and voids support strong optical resonances that can enhance and effectively control light absorption and scattering processes. As such, they provide ideal building blocks for novel, broadband antireflection coatings, light-trapping layers and super-absorbing films. This Review discusses some of the recent developments in the design and implementation of such photonic elements in thin-film photovoltaic cells.

  View details for DOI 10.1038/NMAT3921

  View details for Web of Science ID 000334845600014

  View details for PubMedID 24751773

• Light trapping for solar fuel generation with mie resonances. Nano letters Kim, S. J., Thomann, I., Park, J., Kang, J., Vasudev, A. P., Brongersma, M. L. 2014; 14 (3): 1446-1452

  Abstract

  The implementation of solar fuel generation as a clean, terawatt-scale energy source is critically dependent on the development of high-performance, inexpensive photocatalysts. Many candidate materials, including for example α-Fe2O3 (hematite), suffer from very poor charge transport with minority carrier diffusion lengths that are significantly shorter (nanometer scale) than the absorption depth of light (micrometer scale near the band edge). As a result, most of the photoexcited carriers recombine rather than participate in water-splitting reactions. For this reason, there is a tremendous opportunity for photon management. Plasmon-resonant nanostructures have been employed to effectively enhance light absorption in the near-surface region of photocatalysts, but this approach suffers from intrinsic optical losses in the metal. Here, we circumvent this issue by driving optical resonances in the active photocatalyst material itself. We illustrate that judiciously nanopatterned photocatalysts support optical Mie and guided resonances capable of substantially enhancing the photocarrier generation rate within 10-20 nm from the water/photocatalyst interface.

  View details for DOI 10.1021/nl404575e

  View details for PubMedID 24524658

• Hot-electron photodetection with a plasmonic nanostripe antenna. Nano letters Chalabi, H., Schoen, D., Brongersma, M. L. 2014; 14 (3): 1374-1380

  Abstract

  Planar metal-oxide-metal structures can serve as photodetectors that do not rely on the usual electron-hole pair generation in a semiconductor. Instead, absorbed light in one of the metals can produce a current of hot electrons when the incident photon energy exceeds the oxide barrier energy. Despite the desirable traits of convenient fabrication and room-temperature operation at zero bias of this type of device, the low power conversion efficiency has limited its use. Here, we demonstrate the benefits of reshaping one of the metallic contacts into a plasmonic stripe antenna. We use measurements of the voltage-dependence, spectral-dependence, stripe-width dependence, and polarization-dependence of the photocurrent to show that surface plasmon excitations can result in a favorable redistribution in the electric fields in the stripe that enhances the photocurrent. We also provide a theoretical model that quantifies the spectral photocurrent in terms of the electrical and optical properties of the junction. This model provides an accurate estimate of the bias dependence of the external quantum efficiency of different devices and shows that both the spatial and vectorial properties of the electric field distribution are important to its operation.

  View details for DOI 10.1021/nl4044373

  View details for PubMedID 24502677

• Electrically driven subwavelength optical nanocircuits NATURE PHOTONICS Huang, K. C., Seo, M., Sarmiento, T., Huo, Y., Harris, J. S., Brongersma, M. L. 2014; 8 (3): 244-249

  View details for DOI 10.1038/NPHOTON.2014.2

  View details for Web of Science ID 000332221100017

• Nearly Total Solar Absorption in Ultrathin Nanostructured Iron Oxide for Efficient Photoelectrochemical Water Splitting ACS PHOTONICS Wang, K. X., Wu, Z., Liu, V., Brongersma, M. L., Jaramillo, T. F., Fan, S. 2014; 1 (3): 235-240

  View details for DOI 10.1021/ph4001026

  View details for Web of Science ID 000335802900013

• Deep-subwavelength semiconductor nanowire surface plasmon polariton couplers. Nano letters Landreman, P. E., Brongersma, M. L. 2014; 14 (2): 429-434

  Abstract

  The increased importance of plasmonic devices has prompted a sizable research activity directed toward the development of ultracompact and high-performance couplers. Here, we present a novel scheme for efficient, highly localized, and directional sourcing of surface plasmon polaritons (SPPs) that relies on the excitation of leaky mode optical resonances supported by high-refractive index, semiconductor nanowires. High coupling efficiencies are demonstrated via finite difference frequency domain simulations and experimentally by leakage radiation microscopy. This efficiency is quantified by means of a coupling cross section, the magnitude of which can exceed twice the geometric cross section of the nanowire by exploiting its leaky resonant modes. We provide intuition into why the SPP coupling via certain wire modes is more effective than others based on their symmetry properties. Furthermore, we provide an example showing that dielectric scatterers may perform as well as metallic scatterers in coupling to SPPs.

  View details for DOI 10.1021/nl402980j

  View details for PubMedID 24382272

• Chair Gordon Conference on Plasmonics Brongersma, M., L. 2014
• Electrically-driven surface plasmonic nano-circuits Seo, M., Huang, K. Y., Sarmiento, T., Huo, Y., Harris, J. S., Brongersma, M. L., IEEE IEEE. 2014

  View details for Web of Science ID 000369908603132

• Mimicking Heterostructure Behavior Within a Single Material at Room Temperature Using Strain Sukhdeo, D. S., Nam, D., Kang, J., Petykiewicz, J., Lee, J., Jung, W., Vuckovic, J., Brongersma, M. L., Saraswat, K. C., IEEE IEEE. 2014

  View details for Web of Science ID 000369908602169

• Perfect Sunlight Absorption in Iron Oxide Photoanode Wang, K., Yu, Z., Liu, V., Brongersma, M., Jaramillo, T., Fang, S., IEEE IEEE. 2014

  View details for Web of Science ID 000369908602485

• Electrifying photonic metamaterials for tunable nonlinear optics. Nature communications Kang, L., Cui, Y., Lan, S., Rodrigues, S. P., Brongersma, M. L., Cai, W. 2014; 5: 4680-?

  Abstract

  Metamaterials have not only enabled unprecedented flexibility in producing unconventional optical properties that are not found in nature, they have also provided exciting potential to create customized nonlinear media with high-order properties correlated to linear behaviour. Two particularly compelling directions are active metamaterials, whose optical properties can be purposely tailored by external stimuli in a reversible manner, and nonlinear metamaterials, which enable intensity-dependent frequency conversion of light waves. Here, by exploring the interaction of these two directions, we leverage the electrical and optical functions simultaneously supported in nanostructured metals and demonstrate electrically controlled nonlinear optical processes from a metamaterial. Both second harmonic generation and optical rectification, enhanced by the resonance behaviour in the metamaterial absorber, are modulated externally with applied voltage signals. Our results reveal an opportunity to exploit optical metamaterials as self-contained, dynamic electro-optic systems with intrinsically embedded electrical functions and optical nonlinearities.

  View details for DOI 10.1038/ncomms5680

  View details for PubMedID 25109813

• Two-dimensional chalcogenide nanoplates as tunable metamaterials via chemical intercalation. Nano letters Cha, J. J., Koski, K. J., Huang, K. C., Wang, K. X., Luo, W., Kong, D., Yu, Z., Fan, S., Brongersma, M. L., Cui, Y. 2013; 13 (12): 5913-5918

  Abstract

  New plasmonic materials with tunable properties are in great need for nanophotonics and metamaterials applications. Here we present two-dimensional layered, metal chalcogenides as tunable metamaterials that feature both dielectric photonic and plasmonic modes across a wide spectral range from the infrared to ultraviolet. The anisotropic layered structure allows intercalation of organic molecules and metal atoms at the van der Waals gap of the host chalcogenide, presenting a chemical route to create heterostructures with molecular and atomic precision for photonic and plasmonic applications. This marks a departure from a lithographic method to create metamaterials. Monochromated electron energy-loss spectroscopy in a scanning transmission electron microscope was used to first establish the presence of the dielectric photonic and plasmonic modes in M2E3 (M = Bi, Sb; E = Se, Te) nanoplates and to observe marked changes in these modes after chemical intercalation. We show that these modal properties can also be tuned effectively by more conventional methods such as thickness control and alloy composition of the nanoplates.

  View details for DOI 10.1021/nl402937g

  View details for PubMedID 24266743

• Two-Dimensional Chalcogenide Nanoplates as Tunable Metamaterials via Chemical Intercalation NANO LETTERS Cha, J. J., Koski, K. J., Huang, K. C., Wan, K. X., Luo, W., Kong, D., Yu, Z., Fan, S., Brongersma, M. L., Cui, Y. 2013; 13 (12): 5913-5918

  Abstract

  New plasmonic materials with tunable properties are in great need for nanophotonics and metamaterials applications. Here we present two-dimensional layered, metal chalcogenides as tunable metamaterials that feature both dielectric photonic and plasmonic modes across a wide spectral range from the infrared to ultraviolet. The anisotropic layered structure allows intercalation of organic molecules and metal atoms at the van der Waals gap of the host chalcogenide, presenting a chemical route to create heterostructures with molecular and atomic precision for photonic and plasmonic applications. This marks a departure from a lithographic method to create metamaterials. Monochromated electron energy-loss spectroscopy in a scanning transmission electron microscope was used to first establish the presence of the dielectric photonic and plasmonic modes in M2E3 (M = Bi, Sb; E = Se, Te) nanoplates and to observe marked changes in these modes after chemical intercalation. We show that these modal properties can also be tuned effectively by more conventional methods such as thickness control and alloy composition of the nanoplates.

  View details for DOI 10.1021/nl402937g

  View details for Web of Science ID 000328439200024

• Compact aperiodic metallic groove arrays for unidirectional launching of surface plasmons. Nano letters Huang, X., Brongersma, M. L. 2013; 13 (11): 5420-5424

  Abstract

  The ever-increasing power of computers and the development of new optimization methodologies have enabled the ability to design complex aperiodic devices, which can outperform periodic ones and offer new functionalities. Here, we describe the realization of an ultracompact aperiodic grating coupler capable of selectively launching surface plasmon polaritons (SPPs) in a desired direction. We use a transfer matrix model to facilitate the rapid optimization of such structures. We demonstrate both numerically and experimentally that a structure consisting of five subwavelength grooves patterned into silver can unidirectionally launch SPPs in the visible spectral range with a record right-to-left contrast ratio of 55. The general design principles behind this study can readily be extended to a great diversity of sophisticated aperiodic nanophotonic structures.

  View details for DOI 10.1021/nl402982u

  View details for PubMedID 24127855

• Electro-optical modulation of a silicon waveguide with an "epsilon-near-zero" material. Optics express Vasudev, A. P., Kang, J., Park, J., Liu, X., Brongersma, M. L. 2013; 21 (22): 26387-26397

  Abstract

  Accumulating electrons in transparent conductive oxides such as indium tin oxide (ITO) can induce an "epsilon-near-zero" (ENZ) in the spectral region near the important telecommunications wavelength of λ = 1.55 μm. Here we theoretically demonstrate highly effective optical electro-absorptive modulation in a silicon waveguide overcoated with ITO. This modulator leverages the combination of a local electric field enhancement and increased absorption in the ITO when this material is locally brought into an ENZ state via electrical gating. This leads to large changes in modal absorption upon gating. We find that a 3 dB modulation depth can be achieved in a non-resonant structure with a length under 30 μm for the fundamental waveguide modes of either linear polarization, with absorption contrast values as high as 37. We also show a potential for 100 fJ/bit modulation, with a sacrifice in performance.

  View details for DOI 10.1364/OE.21.026387

  View details for PubMedID 24216861

• Broadband Sharp 90-degree Bends and T-Splitters in Plasmonic Coaxial Waveguides. Nano letters Shin, W., Cai, W., Catrysse, P. B., Veronis, G., Brongersma, M. L., Fan, S. 2013; 13 (10): 4753-4758

  Abstract

  We demonstrate numerically that sharp 90° bends and T-splitters can be designed in plasmonic coaxial waveguides at deep-subwavelength scale to operate without reflection and radiation over a broad range of wavelengths, including the telecommunication wavelength of 1.55 μm. We explain the principles of the operation using a transmission line model of the waveguide in the quasi-static limit. The compact bends and T-splitters open up a new avenue for the design of densely integrated optical circuits with minimal crosstalk.

  View details for DOI 10.1021/nl402335x

  View details for PubMedID 23981038

• Strain-induced pseudoheterostructure nanowires confining carriers at room temperature with nanoscale-tunable band profiles. Nano letters Nam, D., Sukhdeo, D. S., Kang, J., Petykiewicz, J., Lee, J. H., Jung, W. S., Vuckovic, J., Brongersma, M. L., Saraswat, K. C. 2013; 13 (7): 3118-3123

  Abstract

  Semiconductor heterostructures play a vital role in photonics and electronics. They are typically realized by growing layers of different materials, complicating fabrication and limiting the number of unique heterojunctions on a wafer. In this Letter, we present single-material nanowires which behave exactly like traditional heterostructures. These pseudoheterostructures have electronic band profiles that are custom-designed at the nanoscale by strain engineering. Since the band profile depends only on the nanowire geometry with this approach, arbitrary band profiles can be individually tailored at the nanoscale using existing nanolithography. We report the first experimental observations of spatially confined, greatly enhanced (>200×), and wavelength-shifted (>500 nm) emission from strain-induced potential wells that facilitate effective carrier collection at room temperature. This work represents a fundamentally new paradigm for creating nanoscale devices with full heterostructure behavior in photonics and electronics.

  View details for DOI 10.1021/nl401042n

  View details for PubMedID 23758608

• Self-assembly based plasmonic arrays tuned by atomic layer deposition for extreme visible light absorption. Nano letters Hägglund, C., Zeltzer, G., Ruiz, R., Thomann, I., Lee, H., Brongersma, M. L., Bent, S. F. 2013; 13 (7): 3352-3357

  Abstract

  Achieving complete absorption of visible light with a minimal amount of material is highly desirable for many applications, including solar energy conversion to fuel and electricity, where benefits in conversion efficiency and economy can be obtained. On a fundamental level, it is of great interest to explore whether the ultimate limits in light absorption per unit volume can be achieved by capitalizing on the advances in metamaterial science and nanosynthesis. Here, we combine block copolymer lithography and atomic layer deposition to tune the effective optical properties of a plasmonic array at the atomic scale. Critical coupling to the resulting nanocomposite layer is accomplished through guidance by a simple analytical model and measurements by spectroscopic ellipsometry. Thereby, a maximized absorption of light exceeding 99% is accomplished, of which up to about 93% occurs in a volume-equivalent thickness of gold of only 1.6 nm. This corresponds to a record effective absorption coefficient of 1.7 × 10(7) cm(-1) in the visible region, far exceeding those of solid metals, graphene, dye monolayers, and thin film solar cell materials. It is more than a factor of 2 higher than that previously obtained using a critically coupled dye J-aggregate, with a peak width exceeding the latter by 1 order of magnitude. These results thereby substantially push the limits for light harvesting in ultrathin, nanoengineered systems.

  View details for DOI 10.1021/nl401641v

  View details for PubMedID 23805835

• Self-Assembly Based Plasmonic Arrays Tuned by Atomic Layer Deposition for Extreme Visible Light Absorption NANO LETTERS Haegglund, C., Zeltzer, G., Ruiz, R., Thomann, I., Lee, H., Brongersma, M. L., Bent, S. F. 2013; 13 (7): 3352-3357

  Abstract

  Achieving complete absorption of visible light with a minimal amount of material is highly desirable for many applications, including solar energy conversion to fuel and electricity, where benefits in conversion efficiency and economy can be obtained. On a fundamental level, it is of great interest to explore whether the ultimate limits in light absorption per unit volume can be achieved by capitalizing on the advances in metamaterial science and nanosynthesis. Here, we combine block copolymer lithography and atomic layer deposition to tune the effective optical properties of a plasmonic array at the atomic scale. Critical coupling to the resulting nanocomposite layer is accomplished through guidance by a simple analytical model and measurements by spectroscopic ellipsometry. Thereby, a maximized absorption of light exceeding 99% is accomplished, of which up to about 93% occurs in a volume-equivalent thickness of gold of only 1.6 nm. This corresponds to a record effective absorption coefficient of 1.7 × 10(7) cm(-1) in the visible region, far exceeding those of solid metals, graphene, dye monolayers, and thin film solar cell materials. It is more than a factor of 2 higher than that previously obtained using a critically coupled dye J-aggregate, with a peak width exceeding the latter by 1 order of magnitude. These results thereby substantially push the limits for light harvesting in ultrathin, nanoengineered systems.

  View details for DOI 10.1021/nl401641v

  View details for Web of Science ID 000321884300057

• Strain-Induced Pseudoheterostructure Nanowires Confining Carriers at Room Temperature with Nanoscale-Tunable Band Profiles NANO LETTERS Nam, D., Sukhdeo, D. S., Kang, J., Petykiewicz, J., Lee, J. H., Jung, W. S., Vuckovic, J., Brongersma, M. L., Saraswat, K. C. 2013; 13 (7): 3118-3123

  Abstract

  Semiconductor heterostructures play a vital role in photonics and electronics. They are typically realized by growing layers of different materials, complicating fabrication and limiting the number of unique heterojunctions on a wafer. In this Letter, we present single-material nanowires which behave exactly like traditional heterostructures. These pseudoheterostructures have electronic band profiles that are custom-designed at the nanoscale by strain engineering. Since the band profile depends only on the nanowire geometry with this approach, arbitrary band profiles can be individually tailored at the nanoscale using existing nanolithography. We report the first experimental observations of spatially confined, greatly enhanced (>200×), and wavelength-shifted (>500 nm) emission from strain-induced potential wells that facilitate effective carrier collection at room temperature. This work represents a fundamentally new paradigm for creating nanoscale devices with full heterostructure behavior in photonics and electronics.

  View details for DOI 10.1021/nl401042n

  View details for Web of Science ID 000321884300019

• Effects of surface oxide formation on germanium nanowire band-edge photoluminescence APPLIED PHYSICS LETTERS Hashemi, F. S., Thombare, S., Fontcuberta i Morral, A., Brongersma, M. L., McIntyre, P. C. 2013; 102 (25)

  View details for DOI 10.1063/1.4812334

  View details for Web of Science ID 000321145200022

• Geometric light trapping with a V-trap for efficient organic solar cells OPTICS EXPRESS Kim, S. J., Margulis, G. Y., Rim, S., Brongersma, M. L., McGehee, M. D., Peumans, P. 2013; 21 (9): A305-A312

  Abstract

  The efficiency of today's most efficient organic solar cells is primarily limited by the ability of the active layer to absorb all the sunlight. While internal quantum efficiencies exceeding 90% are common, the external quantum efficiency rarely exceeds 70%. Light trapping techniques that increase the ability of a given active layer to absorb light are common in inorganic solar cells but have only been applied to organic solar cells with limited success. Here, we analyze the light trapping mechanism for a cell with a V-shape substrate configuration and demonstrate significantly improved photon absorption in an 5.3%-efficient PCDTBT:PC(70)BM bulk heterojunction polymer solar cell. The measured short circuit current density improves by 29%, in agreement with model predictions, and the power conversion efficiency increases to 7.2%, a 35% improvement over the performance in the absence of a light trap.

  View details for Web of Science ID 000318906500001

• Geometric light trapping with a V-trap for efficient organic solar cells. Optics express Kim, S. J., Margulis, G. Y., Rim, S., Brongersma, M. L., McGehee, M. D., Peumans, P. 2013; 21: A305-12

  Abstract

  The efficiency of today's most efficient organic solar cells is primarily limited by the ability of the active layer to absorb all the sunlight. While internal quantum efficiencies exceeding 90% are common, the external quantum efficiency rarely exceeds 70%. Light trapping techniques that increase the ability of a given active layer to absorb light are common in inorganic solar cells but have only been applied to organic solar cells with limited success. Here, we analyze the light trapping mechanism for a cell with a V-shape substrate configuration and demonstrate significantly improved photon absorption in an 5.3%-efficient PCDTBT:PC(70)BM bulk heterojunction polymer solar cell. The measured short circuit current density improves by 29%, in agreement with model predictions, and the power conversion efficiency increases to 7.2%, a 35% improvement over the performance in the absence of a light trap.

  View details for DOI 10.1364/OE.21.00A305

  View details for PubMedID 24104418

• PLASMONICS Harvest season for hot electrons NATURE NANOTECHNOLOGY Chalabi, H., Brongersma, M. L. 2013; 8 (4): 229-230

  View details for DOI 10.1038/nnano.2013.49

  View details for Web of Science ID 000317046800004

  View details for PubMedID 23552114

• Redesigning Photodetector Electrodes as an Optical Antenna NANO LETTERS Fan, P., Huang, K. C., Cao, L., Brongersma, M. L. 2013; 13 (2): 392-396

  Abstract

  At the nanoscale, semiconductor and metallic structures naturally exhibit strong, tunable optical resonances that can be utilized to enhance light-matter interaction and to dramatically increase the performance of chipscale photonic elements. Here, we demonstrate that the metallic leads used to extract current from a Ge nanowire (NW) photodetector can be redesigned to serve as optical antennas capable of concentrating light in the NW. The NW itself can also be made optically resonant and an overall performance optimization involves a careful tuning of both resonances. We show that such a procedure can result in broadband absorption enhancements of up to a factor 1.7 at a target wavelength of 660 nm and an ability to control the detector's polarization-dependent response. The results of this study demonstrate the critical importance of performing a joint optimization of the electrical and optical properties of the metallic and semiconductor building blocks in optoelectronic devices with nanoscale components.

  View details for DOI 10.1021/nl303535s

  View details for Web of Science ID 000315079500011

  View details for PubMedID 23297673

• The Planar Parabolic Optical Antenna NANO LETTERS Schoen, D. T., Coenen, T., Garcia de Abajo, F. J., Brongersma, M. L., Polman, A. 2013; 13 (1): 188-193

  Abstract

  One of the simplest and most common structures used for directing light in macroscale applications is the parabolic reflector. Parabolic reflectors are ubiquitous in many technologies, from satellite dishes to hand-held flashlights. Today, there is a growing interest in the use of ultracompact metallic structures for manipulating light on the wavelength scale. Significant progress has been made in scaling radiowave antennas to the nanoscale for operation in the visible range, but similar scaling of parabolic reflectors employing ray-optics concepts has not yet been accomplished because of the difficulty in fabricating nanoscale three-dimensional surfaces. Here, we demonstrate that plasmon physics can be employed to realize a resonant elliptical cavity functioning as an essentially planar nanometallic structure that serves as a broadband unidirectional parabolic antenna at optical frequencies.

  View details for DOI 10.1021/nl303850v

  View details for Web of Science ID 000313142300033

  View details for PubMedID 23194111

• Broadband Sharp 90-degree Bends and T-Splitters in Plasmonic Coaxial Waveguides Nano Letters Fan, S., H., Shin, W., Cai, W., S., Catrysse et al., P., B. 2013; 13 (10): 4753-4758

  Abstract

  We demonstrate numerically that sharp 90° bends and T-splitters can be designed in plasmonic coaxial waveguides at deep-subwavelength scale to operate without reflection and radiation over a broad range of wavelengths, including the telecommunication wavelength of 1.55 μm. We explain the principles of the operation using a transmission line model of the waveguide in the quasi-static limit. The compact bends and T-splitters open up a new avenue for the design of densely integrated optical circuits with minimal crosstalk.

  View details for DOI 10.1021/nl402335x

• Plasmonic and Semiconductor Building Blocks for Nanophotonic Devices Brongersma, M. L., IEEE IEEE. 2013

  View details for Web of Science ID 000355262503159

• Plasmonic nano-coaxial waveguides for 90-degree bends and T-splitters Shin, W., Cai, W., Catrysse, P. B., Veronis, G., Brongersma, M. L., Fan, S., IEEE IEEE. 2013

  View details for Web of Science ID 000355262505334

• Optimization of non-periodic plasmonic light-trapping layers for thin-film solar cells. Nature communications Pala, R. A., Liu, J. S., Barnard, E. S., Askarov, D., Garnett, E. C., Fan, S., Brongersma, M. L. 2013; 4: 2095-?

  View details for DOI 10.1038/ncomms3095

  View details for PubMedID 23817445

• Compact Aperiodic Metallic Groove Arrays for Unidirectional Launching of Surface Plasmons, Xinpeng Huang Nano Lett Brongersma, Mark, L., Krishna, C., White, Justin, S., Wahl, P., Brongersma, Mark, L., Miller, David, A.B. 2013; 13: 5420-5424
• Two-Dimensional Chalcogenide Nanoplates as Tunable Metamaterials via Chemical Intercalation Nano Letters Cha, J. 2013; 13: 5913-5918
• Program committee for Section on Light-Matter interactions at the nanoscale Brongersma, M., L. 2013
• Plasmonics: Harvest season for hot electrons Nature Nanotechnology Chalabi, H., van Blaaderen, A., van Dillen, T., Kats, C., M., Velikov, K., Brongersma, M., L. 2013; 8: 229–230
• Geometric tuning of Plasmonic and Semiconductor Resonances in Nanophotonic devices Kenote presentation at Meta 13, Sharjah, Dubai Brongersma, Mark, L., Barnard, Edward, S., Cai, W., Brongersma, Mark, L. 2013
• Program committee for Section on Nanophotonics Brongersma, M., L. 2013
• One of the 5 Meeting Chairs for the 2013 Materials Research Society Spring Meeting. Brongersma, M., L. 2013
• Plasmonic and Semiconductor Building Blocks Brongersma, M., L. 2013
• Optical Nanostructures and Advanced Materials for Photovoltaics Brongersma, M., L. 2013
• Program committee of the SPIE conference on Metamaterials: Fundamentals and Applications Brongersma, M., L. 2013
• Electrically Driven Plasmonic Nanocircuits Breakthrough talk at Nano Meta 2013, Seefeld, Austria Brongersma, Mark, L., Vasudev, Alok, P., Brongersma, Mark, L. 2013
• Program Committee of the Nanometa 2013 conference Brongersma, M., L. 2013
• Optimization of non-periodic plasmonic light-trapping layers for thin-film solar cells. Nature communications Pala, R. A., Liu, J. S., Barnard, E. S., Askarov, D., Garnett, E. C., Fan, S., Brongersma, M. L. 2013; 4: 2095-?

  Abstract

  Non-periodic arrangements of nanoscale light scatterers allow for the realization of extremely effective broadband light-trapping layers for solar cells. However, their optimization is challenging given the massive number of degrees of freedom. Brute-force, full-field electromagnetic simulations are computationally too time intensive to identify high-performance solutions in a vast design space. Here we illustrate how a semi-analytical model can be used to quickly identify promising non-periodic spatial arrangements of nanoscale scatterers. This model only requires basic knowledge of the scattering behaviour of a chosen nanostructure and the waveguiding properties of the semiconductor layer in a cell. Due to its simplicity, it provides new intuition into the ideal amount of disorder in high-performance light-trapping layers. Using simulations and experiments, we demonstrate that arrays of nanometallic stripes featuring a limited amount of disorder, for example, following a quasi-periodic or Fibonacci sequence, can substantially enhance solar absorption over perfectly periodic and random arrays.

  View details for DOI 10.1038/ncomms3095

  View details for PubMedID 23817445

• Plasmonics in optoelectronic devices NANOTECHNOLOGY Demming, A., Brongersma, M., Kim, D. S. 2012; 23 (44)

  View details for DOI 10.1088/0957-4484/23/44/440201

  View details for Web of Science ID 000310574700001

  View details for PubMedID 23079768

• An Electrically-Driven GaAs Nanowire Surface Plasmon Source NANO LETTERS Fan, P., Colombo, C., Huang, K. C., Krogstrup, P., Nygard, J., Fontcuberta i Morral, A., Brongersma, M. L. 2012; 12 (9): 4943-4947

  Abstract

  Over the past decade, the properties of plasmonic waveguides have extensively been studied as key elements in important applications that include biosensors, optical communication systems, quantum plasmonics, plasmonic logic, and quantum-cascade lasers. Whereas their guiding properties are by now fairly well-understood, practical implementation in chipscale systems is hampered by the lack of convenient electrical excitation schemes. Recently, a variety of surface plasmon lasers have been realized, but they have not yet been waveguide-coupled. Planar incoherent plasmonic sources have recently been coupled to plasmonic guides but routing of plasmonic signals requires coupling to linear waveguides. Here, we present an experimental demonstration of electrically driven GaAs nanowire light sources integrated with plasmonic nanostrip waveguides with a physical cross-section of 0.08λ(2). The excitation and waveguiding of surface plasmon-polaritons (SPPs) is experimentally demonstrated and analyzed with the help of full-field electromagnetic simulations. Splitting and routing of the electrically generated SPP signals around 90° bends are also shown. The realization of integrated plasmon sources greatly increases the applicability range of plasmonic waveguides and routing elements.

  View details for DOI 10.1021/nl302521v

  View details for Web of Science ID 000308576000087

  View details for PubMedID 22924961

• Antenna electrodes for controlling electroluminescence NATURE COMMUNICATIONS Huang, K. C., Seo, M., Huo, Y., Sarmiento, T., Harris, J. S., Brongersma, M. L. 2012; 3

  Abstract

  Optical antennas can control the emission from quantum emitters by modifying the local density of optical states via the Purcell effect. A variety of nanometallic antennas have been implemented to enhance and control key photoluminescence properties, such as the decay rate, directionality and polarization. However, their implementation in active devices has been hampered by the need to precisely place emitters near an antenna and to efficiently excite them electrically. Here we illustrate a design methodology for antenna electrodes that for the first time facilitates simultaneous operation as electrodes for current injection and as antennas capable of optically manipulating the electroluminescence. We show that by confining the electrically excited carriers to the vicinity of antenna electrodes and maximizing the optical coupling of the emission to a single, well-defined antenna mode, their electroluminescence can be effectively controlled. This work spurs the development of densely integrated, electrically driven light sources with tailored emission properties.

  View details for DOI 10.1038/ncomms1985

  View details for Web of Science ID 000308801100021

  View details for PubMedID 22893129

• Direct-gap photoluminescence from germanium nanowires PHYSICAL REVIEW B Kawamura, Y., Huang, K. C., Thombare, S. V., Hu, S., Gunji, M., Ishikawa, T., Brongersma, M. L., Itoh, K. M., McIntyre, P. C. 2012; 86 (3)

  View details for DOI 10.1103/PhysRevB.86.035306

  View details for Web of Science ID 000306189300005

• An invisible metal-semiconductor photodetector NATURE PHOTONICS Fan, P., Chettiar, U. K., Cao, L., Afshinmanesh, F., Engheta, N., Brongersma, M. L. 2012; 6 (6): 380-385

  View details for DOI 10.1038/NPHOTON.2012.108

  View details for Web of Science ID 000304598200015

• A micromachining-based technology for enhancing germanium light emission via tensile strain NATURE PHOTONICS Jain, J. R., Hryciw, A., Baer, T. M., Miller, D. A., Brongersma, M. L., Howe, R. T. 2012; 6 (6): 398-405

  View details for DOI 10.1038/NPHOTON.2012.111

  View details for Web of Science ID 000304598200018

• Hybrid Silicon Nanocone-Polymer Solar Cells NANO LETTERS Jeong, S., Garnett, E. C., Wang, S., Yu, Z., Fan, S., Brongersma, M. L., McGehee, M. D., Cui, Y. 2012; 12 (6): 2971-2976

  Abstract

  Recently, hybrid Si/organic solar cells have been studied for low-cost Si photovoltaic devices because the Schottky junction between the Si and organic material can be formed by solution processes at a low temperature. In this study, we demonstrate a hybrid solar cell composed of Si nanocones and conductive polymer. The optimal nanocone structure with an aspect ratio (height/diameter of a nanocone) less than two allowed for conformal polymer surface coverage via spin-coating while also providing both excellent antireflection and light trapping properties. The uniform heterojunction over the nanocones with enhanced light absorption resulted in a power conversion efficiency above 11%. Based on our simulation study, the optimal nanocone structures for a 10 μm thick Si solar cell can achieve a short-circuit current density, up to 39.1 mA/cm(2), which is very close to the theoretical limit. With very thin material and inexpensive processing, hybrid Si nanocone/polymer solar cells are promising as an economically viable alternative energy solution.

  View details for DOI 10.1021/nl300713x

  View details for Web of Science ID 000305106400054

  View details for PubMedID 22545674

• Nanophotonic light trapping with patterned transparent conductive oxides OPTICS EXPRESS Vasudev, A. P., Schuller, J. A., Brongersma, M. L. 2012; 20 (10): A385-A394

  Abstract

  Transparent conductive oxides (TCOs) play a crucial role in solar cells by efficiently transmitting sunlight and extracting photo-generated charge. Here, we show how nanophotonics concepts can be used to transform TCO films into effective photon management layers for solar cells. This is accomplished by patterning the TCO layer present on virtually every thin-film solar cell into an array of subwavelength beams that support optical (Mie) resonances. These resonances can be exploited to concentrate randomly polarized sunlight or to effectively couple it to guided and diffracted modes. We first demonstrate these concepts with a model system consisting of a patterned TCO layer on a thin silicon (Si) film and outline a design methodology for high-performance, TCO-based light trapping coatings. We then show that the short circuit current density from a 300 nm thick amorphous silicon (a-Si) cell with an optimized TCO anti-reflection coating can be enhanced from 19.9 mA/cm2 to 21.1 mA/cm2, out of a possible 26.0 mA/cm2, by using an optimized nanobeam array. The key differences and advantages over plasmonic light trapping layers will be discussed.

  View details for Web of Science ID 000303879700002

  View details for PubMedID 22712089

• Electroluminescence from strained germanium membranes and implications for an efficient Si-compatible laser APPLIED PHYSICS LETTERS Nam, D., Sukhdeo, D., Cheng, S., Roy, A., Huang, K. C., Brongersma, M., Nishi, Y., Saraswat, K. 2012; 100 (13)

  View details for DOI 10.1063/1.3699224

  View details for Web of Science ID 000302230800012

• Self-limited plasmonic welding of silver nanowire junctions NATURE MATERIALS Garnett, E. C., Cai, W., Cha, J. J., Mahmood, F., Connor, S. T., Christoforo, M. G., Cui, Y., McGehee, M. D., Brongersma, M. L. 2012; 11 (3): 241-249

  Abstract

  Nanoscience provides many strategies to construct high-performance materials and devices, including solar cells, thermoelectrics, sensors, transistors, and transparent electrodes. Bottom-up fabrication facilitates large-scale chemical synthesis without the need for patterning and etching processes that waste material and create surface defects. However, assembly and contacting procedures still require further development. Here, we demonstrate a light-induced plasmonic nanowelding technique to assemble metallic nanowires into large interconnected networks. The small gaps that form naturally at nanowire junctions enable effective light concentration and heating at the point where the wires need to be joined together. The extreme sensitivity of the heating efficiency on the junction geometry causes the welding process to self-limit when a physical connection between the wires is made. The localized nature of the heating prevents damage to low-thermal-budget substrates such as plastics and polymer solar cells. This work opens new avenues to control light, heat and mass transport at the nanoscale.

  View details for DOI 10.1038/NMAT3238

  View details for Web of Science ID 000300625500025

  View details for PubMedID 22306769

• Thermal Stability and Surface Passivation of Ge Nanowires Coated by Epitaxial SiGe Shells NANO LETTERS Hu, S., Kawamura, Y., Huang, K. C., Li, Y., Marshall, A. F., Itoh, K. M., Brongersma, M. L., McIntyre, P. C. 2012; 12 (3): 1385-1391

  Abstract

  Epitaxial growth of a highly strained, coherent SiGe alloy shell around a Ge nanowire core is investigated as a method to achieve surface passivation and carrier confinement, important in realizing nanowire devices. The high photoluminescence intensity observed from the core-shell nanowires with spectral features similar to that of bulk Ge indicates effective surface passivation. Thermal stability of these core-shell heterostructures has been systematically investigated, with a method demonstrated to avoid misfit strain relaxation during postgrowth annealing.

  View details for DOI 10.1021/nl204053w

  View details for Web of Science ID 000301406800046

  View details for PubMedID 22364183

• Metal-dielectric-metal surface plasmon-polariton resonators PHYSICAL REVIEW B Chandran, A., Barnard, E. S., White, J. S., Brongersma, M. L. 2012; 85 (8)

  View details for DOI 10.1103/PhysRevB.85.085416

  View details for Web of Science ID 000300090800004

• Ultrathin crystalline-silicon solar cells with embedded photonic crystals APPLIED PHYSICS LETTERS Mallick, S. B., Agrawal, M., Wangperawong, A., Barnard, E. S., Singh, K. K., Visser, R. J., Brongersma, M. L., Peumans, P. 2012; 100 (5)

  View details for DOI 10.1063/1.3680602

  View details for Web of Science ID 000300065300069

• Highly-Strained Germanium as a Gain Medium for Silicon-Compatible Lasers Conference on Lasers and Electro-Optics (CLEO) Sukhdeo, D., Nam, D., Cheng, S., Yuan, Z., Roy, A., Huang, K. C., Brongersma, M., Nishi, Y., Saraswat, K. IEEE. 2012

  View details for Web of Science ID 000310362401035

• Rolling mask nanolithography: the pathway to large area and low cost nanofabrication Conference on Advanced Fabrication Technologies for Micro/Nano Optics and Photonics V Kobrin, B., Barnard, E. S., Brongersma, M. L., Kwak, M. K., Guo, L. J. SPIE-INT SOC OPTICAL ENGINEERING. 2012

  View details for DOI 10.1117/12.910158

  View details for Web of Science ID 000302640700015

• Routing and photodetection in subwavelength plasmonic slot waveguides NANOPHOTONICS Ly-Gagnon, D., Balram, K. C., White, J. S., Wahl, P., Brongersma, M. L., Miller, D. A. 2012; 1 (1): 9-16

  View details for DOI 10.1515/nanoph-2012-0002

  View details for Web of Science ID 000208897700003

• Measurement of the polarization state of light using an integrated plasmonic polarimeter NANOPHOTONICS Afshinmanesh, F., White, J. S., Cai, W., Brongersma, M. L. 2012; 1 (2): 125-129

  View details for DOI 10.1515/nanoph-2012-0004

  View details for Web of Science ID 000208897900001

• Editorial Board of the Journal Nano-Photonics Brongersma, Mark, L., Jun, Y. C., Brongersma, Mark, L. 2012
• Editorial Advisory Board of the Journal Advanced Optical Materials Brongersma, Mark, L., Agrawal, M., Wangperawong, A., Barnard, Edward, S., Singh, Kaushal, K., Visser, Robert, J. 2012
• Electrical control of plasmonic Nanodevices SPIE Newsroom. Cai, W., Sukhdeo, D., Roy, A., Balram, K., Cheng, S., Huang, K. C., Brongersma, M. L. 2012

  View details for DOI 10.1117/2.1201112.004060

• Optical antennas for information technology and energy harvesting Optical Antenna Theory, Design and Applications Brongersma, M. edited by Alù, A., Engheta, N. Cambridge University Press. 2012: 1
• Plasmonics Short course at the Conference on Lasers and Electro-optics CLEO US, San Jose Brongersma, Mark, L., Selker, Mark, D., Catrysse, Peter, B., Brongersma, Mark, L. 2012
• Plasmonic and Semiconductor Building Blocks for Hybrid Nanophotonic Devices Brongersma, M., L. 2012
• International program Committee of the 12th Near-field Optics Brongersma, M., L. 2012
• Vice Chair Gordon Conference on Plasmonics Brongersma, M., L. 2012
• Rolling mask nanolithography: the pathway to large area and low cost nanofabrication Kobrin, B., Barnard, Edward, S., Brongersma, Mark, L., Kwak, M. K., Guo, L., Jay 2012
• Measurement of the polarization state of light using an integrated plasmonic polarimeter Nanophotonics Afshinmanesh, F., Brongersma, Mark, L. 2012; 1: 125–129
• Smart & Adaptive Optics Brongersma, M., L. 2012
• Excitons and Plasmon Resonances in Nanostructures III Brongersma, M., L. 2012
• Routing and photodetection in subwavelength plasmonic slot waveguides Nanophotonics Ly-Gagnon 1, D., Brongersma, M., L., Snoeks, E., Polman, A. 2012; 1: 9–16
• Metal-dielectric-metal surface plasmon-polariton resonators Phys. Rev Chandran, A., White, Justin, S., Park, J., Schuller, Jon, A., Clemens, Bruce, M., Brongersma, Mark, L. 2012; B 85: 85416
• Antenna electrodes for optical sources and solar cells Keynote presentation at the SPIE Annual Meeting, San Diego Brongersma, Mark, L., Thombare, S., Morral, A. F., Brongersma, Mark, L., McIntyre, Paul, C. 2012
• Strained germanium thin film membrane on silicon substrate for optoelectronics OPTICS EXPRESS Nam, D., Sukhdeo, D., Roy, A., Balram, K., Cheng, S., Huang, K. C., Yuan, Z., Brongersma, M., Nishi, Y., Miller, D., Saraswat, K. 2011; 19 (27): 25866-25872

  Abstract

  This work presents a novel method to introduce a sustainable biaxial tensile strain larger than 1% in a thin Ge membrane using a stressor layer integrated on a Si substrate. Raman spectroscopy confirms 1.13% strain and photoluminescence shows a direct band gap reduction of 100meV with enhanced light emission efficiency. Simulation results predict that a combination of 1.1% strain and heavy n(+) doping reduces the required injected carrier density for population inversion by over a factor of 60. We also present the first highly strained Ge photodetector, showing an excellent responsivity well beyond 1.6um.

  View details for PubMedID 22274174

• Rapid computation of light scattering from aperiodic plasmonic structures PHYSICAL REVIEW B Huang, X., Brongersma, M. L. 2011; 84 (24)

  View details for DOI 10.1103/PhysRevB.84.245120

  View details for Web of Science ID 000298561000001

• Engineering light absorption in single-nanowire solar cells with metal nanoparticles NEW JOURNAL OF PHYSICS Colombo, C., Krogstrup, P., Nygard, J., Brongersma, M. L., Fontcuberta i Morral, A. 2011; 13

  View details for DOI 10.1088/1367-2630/13/12/123026

  View details for Web of Science ID 000299006200005

• A submicron plasmonic dichroic splitter NATURE COMMUNICATIONS Liu, J. S., Pala, R. A., Afshinmanesh, F., Cai, W., Brongersma, M. L. 2011; 2

  Abstract

  Spectral imaging and sensing techniques, new solar cell designs and wavelength-division multiplexing in optical communication rely on structures that collect and sort photons by wavelength. The strong push for chip-scale integration of such optical components has necessitated ultracompact, planar structures, and fomented great interest in identifying the smallest possible devices. Consequently, novel micro-ring, photonic crystal and plasmonic solutions have emerged. Meanwhile, the optical coupling of subwavelength plasmonic structures supporting a very limited number of modes has also enabled new functionalities, including Fano resonances and structural electromagnetically-induced transparency. Here we show how two similarly sized subwavelength metal grooves can form an ultracompact submicron plasmonic dichroic splitter. Each groove supports just two electromagnetic modes of opposite symmetry that allows independent control of how a groove collects free-space photons and directs surface plasmon polaritons. These results show how the symmetry of electromagnetic modes can be exploited to build compact optical components.

  View details for DOI 10.1038/ncomms1537

  View details for Web of Science ID 000297686500012

  View details for PubMedID 22068592

• Tensile-strained germanium-on-insulator substrate fabrication for silicon-compatible optoelectronics OPTICAL MATERIALS EXPRESS Jain, J. R., Ly-Gagnon, D., Balram, K. C., White, J. S., Brongersma, M. L., Miller, D. A., Howe, R. T. 2011; 1 (6): 1121-1126

  View details for Web of Science ID 000299048700007

• Imaging the Hidden Modes of Ultrathin Plasmonic Strip Antennas by Cathodoluminescence NANO LETTERS Barnard, E. S., Coenen, T., Vesseur, E. J., Polman, A., Brongersma, M. L. 2011; 11 (10): 4265-4269

  Abstract

  We perform spectrally resolved cathodoluminescence (CL) imaging nanoscopy using a 30 keV electron beam to identify the resonant modes of an ultrathin (20 nm), laterally tapered plasmonic Ag nanostrip antenna. We resolve with deep-subwavelength resolution four antenna resonances (resonance orders m = 2-5) that are ascribed to surface plasmon polariton standing waves that are confined on the strip. We map the local density of states on the strip surface and show that it has contributions from symmetric and antisymmetric surface plasmon polariton modes, each with a very different mode index. This work illustrates the power of CL experiments that can visualize hidden modes that for symmetry reasons have been elusive in optical light scattering experiments.

  View details for DOI 10.1021/nl202256k

  View details for Web of Science ID 000295667000041

  View details for PubMedID 21879729

• Power flow from a dipole emitter near an optical antenna OPTICS EXPRESS Huang, K. C., Jun, Y. C., Seo, M., Brongersma, M. L. 2011; 19 (20): 19084-19092

  Abstract

  Current methods to calculate the emission enhancement of a quantum emitter coupled to an optical antenna of arbitrary geometry rely on analyzing the total Poynting vector power flow out of the emitter or the dyadic Green functions from full-field numerical simulations. Unfortunately, these methods do not provide information regarding the nature of the dominant energy decay pathways. We present a new approach that allows for a rigorous separation, quantification, and visualization of the emitter output power flow captured by an antenna and the subsequent reradiation power flow to the far field. Such analysis reveals unprecedented details of the emitter/antenna coupling mechanisms and thus opens up new design strategies for strongly interacting emitter/antenna systems used in sensing, active plasmonics and metamaterials, and quantum optics.

  View details for Web of Science ID 000295373800033

  View details for PubMedID 21996849

• Electrically Controlled Nonlinear Generation of Light with Plasmonics SCIENCE Cai, W., Vasudev, A. P., Brongersma, M. L. 2011; 333 (6050): 1720-1723

  Abstract

  Plasmonics provides a route to develop ultracompact optical devices on a chip by using extreme light concentration and the ability to perform simultaneous electrical and optical functions. These properties also make plasmonics an ideal candidate for dynamically controlling nonlinear optical interactions at the nanoscale. We demonstrate electrically tunable harmonic generation of light from a plasmonic nanocavity filled with a nonlinear medium. The metals that define the cavity also serve as electrodes that can generate high direct current electric fields across the nonlinear material. A fundamental wave at 1.56 micrometers was frequency doubled and modulated in intensity by applying a moderate external voltage to the electrodes, yielding a voltage-dependent nonlinear generation with a normalized magnitude of ~7% per volt.

  View details for DOI 10.1126/science.1207858

  View details for Web of Science ID 000295121500034

  View details for PubMedID 21940887

• Photocurrent mapping of near-field optical antenna resonances NATURE NANOTECHNOLOGY Barnard, E. S., Pala, R. A., Brongersma, M. L. 2011; 6 (9): 588-593

  Abstract

  An increasing number of photonics applications make use of nanoscale optical antennas that exhibit a strong, resonant interaction with photons of a specific frequency. The resonant properties of such antennas are conventionally characterized by far-field light-scattering techniques. However, many applications require quantitative knowledge of the near-field behaviour, and existing local field measurement techniques provide only relative, rather than absolute, data. Here, we demonstrate a photodetector platform that uses a silicon-on-insulator substrate to spectrally and spatially map the absolute values of enhanced fields near any type of optical antenna by transducing local electric fields into photocurrent. We are able to quantify the resonant optical and materials properties of nanoscale (∼50 nm) and wavelength-scale (∼1 µm) metallic antennas as well as high-refractive-index semiconductor antennas. The data agree well with light-scattering measurements, full-field simulations and intuitive resonator models.

  View details for DOI 10.1038/NNANO.2011.131

  View details for Web of Science ID 000294550000016

  View details for PubMedID 21857687

• Plasmon Enhanced Solar-to-Fuel Energy Conversion NANO LETTERS Thomann, I., Pinaud, B. A., Chen, Z., Clemens, B. M., Jaramillo, T. F., Brongersma, M. L. 2011; 11 (8): 3440-3446

  Abstract

  Future generations of photoelectrodes for solar fuel generation must employ inexpensive, earth-abundant absorber materials in order to provide a large-scale source of clean energy. These materials tend to have poor electrical transport properties and exhibit carrier diffusion lengths which are significantly shorter than the absorption depth of light. As a result, many photoexcited carriers are generated too far from a reactive surface and recombine instead of participating in solar-to-fuel conversion. We demonstrate that plasmonic resonances in metallic nanostructures and multilayer interference effects can be engineered to strongly concentrate sunlight close to the electrode/liquid interface, precisely where the relevant reactions take place. On comparison of spectral features in the enhanced photocurrent spectra to full-field electromagnetic simulations, the contribution of surface plasmon excitations is verified. These results open the door to the optimization of a wide variety of photochemical processes by leveraging the rapid advances in the field of plasmonics.

  View details for DOI 10.1021/nl201908s

  View details for Web of Science ID 000293665600066

  View details for PubMedID 21749077

• Sombrero-Shaped Plasmonic Nanoparticles with Molecular-Level Sensitivity and Multifunctionality ACS NANO Wi, J., Barnard, E. S., Wilson, R. J., Zhang, M., Tang, M., Brongersma, M. L., Wang, S. X. 2011; 5 (8): 6449-6457

  Abstract

  We demonstrate top-down synthesis of monodisperse plasmonic nanoparticles designed to contain internal Raman hot spots. Our Raman-active nanoparticles are fabricated using nanoimprint lithography and thin-film deposition and are composed of novel internal structures with sublithographic dimensions: a disk-shaped Ag core, a Petri-dish-shaped SiO(2) base whose inner surface is coated with Ag film, and a sub-10 nm scale circular gap between the core and the base. Confocal Raman measurements and electromagnetic simulations show that Raman hot spots appear at the inside perimeter of individual nanoparticles and serve as the source of a 1000-fold improvement of minimum molecular detection level that enables detection of signals from a few molecules near hot spots. A multimodality version of these nanoparticles, which includes the functionality offered by magnetic multilayers, is also demonstrated. These results illustrate the potential of direct fabrication for creating exotic monodisperse nanoparticles, which combine engineered internal nanostructures and multilayer composite materials, for use in nanoparticle-based molecular imaging and detection.

  View details for DOI 10.1021/nn201649n

  View details for Web of Science ID 000294085400044

  View details for PubMedID 21732686

  View details for PubMedCentralID PMC3160147

• Multiple-Wavelength Focusing of Surface Plasmons with a Nonperiodic Nanoslit Coupler NANO LETTERS Tanemura, T., Balram, K. C., Ly-Gagnon, D., Wahl, P., White, J. S., Brongersma, M. L., Miller, D. A. 2011; 11 (7): 2693-2698

  Abstract

  A novel type of multiple-wavelength focusing plasmonic coupler based on a nonperiodic nanoslit array is designed and experimentally demonstrated. An array of nanoslits patterned on a thin metal film is used to couple free-space light into surface plasmon polaritons (SPPs) and simultaneously focus different-wavelength SPPs into arbitrary predefined locations in the two-dimensional plane. We design and fabricate a compact triplexer on a glass substrate with an integrated silicon photodetector. The photocurrent spectra demonstrate that the incident light is effectively coupled to SPPs and routed into three different focal spots depending on the wavelength. The proposed scheme provides a simple method of building wavelength-division multiplexing and spectral filtering elements, integrated with other plasmonic and optoelectronic devices.

  View details for DOI 10.1021/nl200938h

  View details for Web of Science ID 000292849400022

  View details for PubMedID 21627101

• Plasmonic beaming and active control over fluorescent emission NATURE COMMUNICATIONS Jun, Y. C., Huang, K. C., Brongersma, M. L. 2011; 2

  Abstract

  Nanometallic optical antennas are rapidly gaining popularity in applications that require exquisite control over light concentration and emission processes. The search is on for high-performance antennas that offer facile integration on chips. Here we demonstrate a new, easily fabricated optical antenna design that achieves an unprecedented level of control over fluorescent emission by combining concepts from plasmonics, radiative decay engineering and optical beaming. The antenna consists of a nanoscale plasmonic cavity filled with quantum dots coupled to a miniature grating structure that can be engineered to produce one or more highly collimated beams. Electromagnetic simulations and confocal microscopy were used to visualize the beaming process. The metals defining the plasmonic cavity can be utilized to electrically control the emission intensity and wavelength. These findings facilitate the realization of a new class of active optical antennas for use in new optical sources and a wide range of nanoscale optical spectroscopy applications.

  View details for DOI 10.1038/ncomms1286

  View details for Web of Science ID 000289983800021

  View details for PubMedID 21505439

• Optical Coupling of Deep-Subwavelength Semiconductor Nanowires NANO LETTERS Cao, L., Fan, P., Brongersma, M. L. 2011; 11 (4): 1463-1468

  Abstract

  Systems of coupled resonators manifest a myriad of exciting fundamental physical phenomena. Analogous to the synthesis of molecules from single atoms, the construction of photonic molecules from stand-alone optical resonators represents a powerful strategy to realize novel functionalities. The coupling of high quality factor (Q) dielectric and semiconductor microresonators is by now well-understood and chipscale applications are abound. The coupling behavior of low-Q nanometallic structures has also been exploited to realize high-performance plasmonic devices and metamaterials. Although dense arrays of semiconductor nanoparticles and nanowires (NWs) find increasing use in optoelectronic devices, their photonic coupling has remained largely unexplored. These high refractive index nano-objects can serve as low-Q optical antennas that can effectively receive and broadcast light. We demonstrate that the broad band antenna response of a pair of NWs can be tuned significantly by engineering their optical coupling and develop an intuitive coupled-mode theory to explain our observations.

  View details for DOI 10.1021/nl1040429

  View details for Web of Science ID 000289341500013

  View details for PubMedID 21443245

• Atomic Layer Deposition of Lead Sulfide Quantum Dots on Nanowire Surfaces NANO LETTERS Dasgupta, N. P., Jung, H. J., Trejo, O., McDowell, M. T., Hryciw, A., Brongersma, M., Sinclair, R., Prinz, F. B. 2011; 11 (3): 934-940

  Abstract

  Quantum dots provide unique advantages in the design of novel optoelectronic devices owing to the ability to tune their properties as a function of size. Here we demonstrate a new technique for fabrication of quantum dots during the nucleation stage of atomic layer deposition (ALD) of PbS. Islands with sub-10 nm diameters were observed during the initial ALD cycles by transmission electron microscopy, and in situ observations of the coalescence and sublimation behavior of these islands show the possibility of further modifying the size and density of dots by annealing. The ALD process can be used to cover high-aspect-ratio nanostructures, as demonstrated by the uniform coating of a Si nanowire array with a single layer of PbS quantum dots. Photoluminescence measurements on the quantum dot/nanowire composites show a blue shift when the number of ALD cycles is decreased, suggesting a route to fabricate unique three-dimensional nanostructured devices such as solar cells.

  View details for DOI 10.1021/nl103001h

  View details for Web of Science ID 000288061500003

  View details for PubMedID 21319844

• Thermo-optic tuning of erbium-doped amorphous silicon nitride microdisk resonators APPLIED PHYSICS LETTERS Hryciw, A. C., Kekatpure, R. D., Yerci, S., Dal Negro, L., Brongersma, M. L. 2011; 98 (4)

  View details for DOI 10.1063/1.3545845

  View details for Web of Science ID 000286676600002

• Plasmonic Dye-Sensitized Solar Cells ADVANCED ENERGY MATERIALS Ding, I., Zhu, J., Cai, W., Moon, S., Cai, N., Wang, P., Zakeeruddin, S. M., Graetzel, M., Brongersma, M. L., Cui, Y., McGehee, M. D. 2011; 1 (1): 52-57

  View details for DOI 10.1002/aenm.201000041

  View details for Web of Science ID 000291725000004

• Applications: Nanophotonics and Plasmonics NANOTECHNOLOGY RESEARCH DIRECTIONS FOR SOCIETAL NEEDS IN 2020: RETROSPECTIVE AND OUTLOOK Hu, E. L., Brongersma, M., Baca, A., Roco, M., Mirkin, C., Hersam, M. 2011; 1: 417–44

  View details for DOI 10.1007/978-94-007-1168-6_10

  View details for Web of Science ID 000293209300010

• Modification of the spontaneous emission rate of nitrogen-vacancy centers in diamond by coupling to plasmons Conference on Advances in Photonics of Quantum Computing, Memory, and Communication IV Faraon, A., Jun, Y. C., Barclay, P. E., Fu, K. C., Santori, C. M., Brongersma, M. L., Beausoleil, R. G. SPIE-INT SOC OPTICAL ENGINEERING. 2011

  View details for DOI 10.1117/12.874221

  View details for Web of Science ID 000293702100018

• Effect of illlumination on thermionic emission from microfabricated silicon carbide structures 16th International Solid-State Sensors, Actuators and Microsystems, Beijing, China Lee, J., H., Brongersma, Mark, L. 2011
• Modification of the spontaneous emission rate of nitrogen-vacancy centers in diamond by coupling to plasmons Advances in Photonics of Quantum Computing, Memory, and Communication IV, San Francisco, CA Faraon, A., White, J., Barnard, E., Liu, J., Brongersma, Mark, L. 2011
• Hybrid Semiconductor/Plasmonic Devices for Nanophotonics Keynote presentation at the SPIE Annual Meeting, San Diego Brongersma, Mark, L., Fan, P., Vasudev, Alok, P., White, Justin, S., Yu, Z., Cai, W. 2011
• Guest Editor for special Green Photonics issue for the Journal of Optics Brongersma, Mark, L., Pala, R., Brongersma, Mark, L. 2011
• Plasmons and rust for solar energy conversion Thomann, I., Pinaud, B., Pala, R., Seo, M., Chen, Z., Jaramillo, T., Brongersma, M. L. 2011
• Nanoplasmonics course at the Conference on Lasers and Electro-optics CLEO Europe, Munich, Germany Brongersma, Mark, L., Brongersma, M. L. 2011
• Program Committee for the Annual OSA meeting on Integrated Photonics Research Brongersma, M., L. 2011
• Guest Editor for a special Plasmonics issue for the journal Nanotechnology Brongersma, Mark, L., Park, J., Fan, P., Clemens, B., Brongersma, Mark, L. 2011
• Submicron plasmonic dichroic splitter Nature Communications Liu, John, S.Q. 2011; 2: 525
• Nanowire Solar Cells ANNUAL REVIEW OF MATERIALS RESEARCH, VOL 41 Garnett, E. C., Brongersma, M. L., Cui, Y., McGehee, M. D. 2011; 41: 269-295

  View details for DOI 10.1146/annurev-matsci-062910-100434

  View details for Web of Science ID 000294028600011

• An Integrated Plasmonic Polarimeter Conference on Lasers and Electro-Optics (CLEO) Afshinmanesh, F., White, J. S., Cai, W., Brongersma, M. L. IEEE. 2011

  View details for Web of Science ID 000295612404094

• Strained Germanium Membrane using Thin Film Stressor for High Efficiency Laser Conference on Lasers and Electro-Optics (CLEO) Nam, D., Roy, A. M., Huang, K. C., Brongersma, M. L., Saraswat, K. C. IEEE. 2011

  View details for Web of Science ID 000295612403095

• Elements for Plasmonic Nanocircuits with Three-Dimensional Slot Waveguides ADVANCED MATERIALS Cai, W., Shin, W., Fan, S., Brongersma, M. L. 2010; 22 (45): 5120-?

  View details for DOI 10.1002/adma.201001440

  View details for Web of Science ID 000285396400010

  View details for PubMedID 20859937

• High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells NANO LETTERS Hardin, B. E., Yum, J., Hoke, E. T., Jun, Y. C., Pechy, P., Torres, T., Brongersma, M. L., Nazeeruddin, M. K., Graetzel, M., McGehee, M. D. 2010; 10 (8): 3077-3083

  Abstract

  The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (ETE) of 96% inside TT1-covered, mesostructured TiO(2) films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients.

  View details for DOI 10.1021/nl1016688

  View details for Web of Science ID 000280728900058

  View details for PubMedID 20617816

• Response to "Comment on 'Energy transfer in nanowire solar cells with photon-harvesting shells'" [J. Appl. Phys. 105, 124509 (2009)] JOURNAL OF APPLIED PHYSICS Peters, C. H., Guichard, A. R., Hryciw, A. C., Brongersma, M. L., McGehee, M. D. 2010; 108 (2)

  View details for DOI 10.1063/1.3452392

  View details for Web of Science ID 000280909900118

• Tuning the Color of Silicon Nanostructures NANO LETTERS Cao, L., Fan, P., Barnard, E. S., Brown, A. M., Brongersma, M. L. 2010; 10 (7): 2649-2654

  Abstract

  Empowering silicon (Si) with optical functions constitutes a very important challenge in photonics. The scalable fabrication capabilities for this earth-abundant, environmentally friendly material are unmatched in sophistication and can be unleashed to realize a plethora of high-performance photonic functionalities that find application in information, bio-, display, camouflage, ornamental, and energy technologies. Nanofashioning represents a general strategy to turn Si into a useful optical material and Si structures have already been engineered to enable light emission, optical cloaking, waveguiding, nonlinear optics, enhanced light absorption, and sensing. Here, we demonstrate that a wide spectrum of colors can be generated by harnessing the strong resonant light scattering properties of Si nanostructures under white light illumination. The ability to engineer such colors in a predetermined fashion through a choice of the structure size, dielectric environment, and illumination conditions opens up entirely new applications of Si and puts this material in a new light.

  View details for DOI 10.1021/nl1013794

  View details for Web of Science ID 000280416200059

  View details for PubMedID 20507083

• NANOSCALE OPTICS Plasmonics gets transformed NATURE NANOTECHNOLOGY Cai, W., Brongersma, M. L. 2010; 5 (7): 485-486

  View details for Web of Science ID 000280529800008

  View details for PubMedID 20606641

• Phase-Coupled Plasmon-Induced Transparency PHYSICAL REVIEW LETTERS Kekatpure, R. D., Barnard, E. S., Cai, W., Brongersma, M. L. 2010; 104 (24)

  Abstract

  We demonstrate the existence of electromagnetically-induced-transparency (EIT-)like spectral response in a system of nanoscale plasmonic resonator antennas coupled by means of a single-mode silicon waveguide. Our proposed scheme exploits the phase of the coupling between the antennas in contrast with the existing plasmonic approaches that rely on the strength of direct, near-field coupling of nanometallic elements. Quality factors of over 100 and group indices of over 10 are readily achieved at near-infrared frequencies by a single unit in ≈1  μm2 of total device footprint, representing a more than two orders size reduction over corresponding dielectric EIT structures. By obviating the need for a near-field interaction, the phase-coupling scheme also facilitates an improved access to the coupling medium between the resonators thereby paving the way toward dynamic control of their sharp EIT-like spectral response.

  View details for DOI 10.1103/PhysRevLett.104.243902

  View details for Web of Science ID 000278884900001

  View details for PubMedID 20867303

• Strong Modification of Quantum Dot Spontaneous Emission via Gap Plasmon Coupling in Metal Nanoslits JOURNAL OF PHYSICAL CHEMISTRY C Jun, Y. C., Pala, R., Brongersma, M. L. 2010; 114 (16): 7269-7273

  View details for DOI 10.1021/jp9083376

  View details for Web of Science ID 000276889300009

• APPLIED PHYSICS The Case for Plasmonics SCIENCE Brongersma, M. L., Shalaev, V. M. 2010; 328 (5977): 440-441

  View details for DOI 10.1126/science.1186905

  View details for Web of Science ID 000276952400023

  View details for PubMedID 20413483

• Resonant Germanium Nanoantenna Photodetectors NANO LETTERS Cao, L., Park, J., Fan, P., Clemens, B., Brongersma, M. L. 2010; 10 (4): 1229-1233

  Abstract

  On-chip optical interconnection is considered as a substitute for conventional electrical interconnects as microelectronic circuitry continues to shrink in size. Central to this effort is the development of ultracompact, silicon-compatible, and functional optoelectronic devices. Photodetectors play a key role as interfaces between photonics and electronics but are plagued by a fundamental efficiency-speed trade-off. Moreover, engineering of desired wavelength and polarization sensitivities typically requires construction of space-consuming components. Here, we demonstrate how to overcome these limitations in a nanoscale metal-semiconductor-metal germanium photodetector for the optical communications band. The detector capitalizes on antenna effects to dramatically enhance the photoresponse (>25-fold) and to enable wavelength and polarization selectivity. The electrical design featuring asymmetric metallic contacts also enables ultralow dark currents (approximately 20 pA), low power consumption, and high-speed operation (>100 GHz). The presented high-performance photodetection scheme represents a significant step toward realizing integrated on-chip communication and manifests a new paradigm for developing miniaturized optoelectronics components.

  View details for DOI 10.1021/nl9037278

  View details for Web of Science ID 000276557100024

  View details for PubMedID 20230043

• Spatially resolved Raman spectroscopy on indium-catalyzed core-shell germanium nanowires: size effects NANOTECHNOLOGY Xiang, Y., Zardo, I., Cao, L. Y., Garma, T., Heiss, M., Morante, J. R., Arbiol, J., Brongersma, M. L., Morral, A. F. 2010; 21 (10)

  Abstract

  The structure of indium-catalyzed germanium nanowires is investigated by atomic force microscopy, scanning confocal Raman spectroscopy and transmission electron microscopy. The nanowires are formed by a crystalline core and an amorphous shell. We find that the diameter of the crystalline core varies along the nanowire, down to few nanometers. Phonon confinement effects are observed in the regions where the crystalline region is the thinnest. The results are consistent with the thermally insulating behavior of the core-shell nanowires.

  View details for DOI 10.1088/0957-4484/21/10/105703

  View details for Web of Science ID 000274572900026

  View details for PubMedID 20154375

• Plasmonics for extreme light concentration and manipulation NATURE MATERIALS Schuller, J. A., Barnard, E. S., Cai, W., Jun, Y. C., White, J. S., Brongersma, M. L. 2010; 9 (3): 193-204

  Abstract

  The unprecedented ability of nanometallic (that is, plasmonic) structures to concentrate light into deep-subwavelength volumes has propelled their use in a vast array of nanophotonics technologies and research endeavours. Plasmonic light concentrators can elegantly interface diffraction-limited dielectric optical components with nanophotonic structures. Passive and active plasmonic devices provide new pathways to generate, guide, modulate and detect light with structures that are similar in size to state-of-the-art electronic devices. With the ability to produce highly confined optical fields, the conventional rules for light-matter interactions need to be re-examined, and researchers are venturing into new regimes of optical physics. In this review we will discuss the basic concepts behind plasmonics-enabled light concentration and manipulation, make an attempt to capture the wide range of activities and excitement in this area, and speculate on possible future directions.

  View details for DOI 10.1038/NMAT2630

  View details for Web of Science ID 000274700900013

  View details for PubMedID 20168343

• Semiconductor Nanowire Optical Antenna Solar Absorbers NANO LETTERS Cao, L., Fan, P., Vasudev, A. P., White, J. S., Yu, Z., Cai, W., Schuller, J. A., Fan, S., Brongersma, M. L. 2010; 10 (2): 439-445

  Abstract

  Photovoltaic (PV) cells can serve as a virtually unlimited clean source of energy by converting sunlight into electrical power. Their importance is reflected in the tireless efforts that have been devoted to improving the electrical and structural properties of PV materials. More recently, photon management (PM) has emerged as a powerful additional means to boost energy conversion efficiencies. Here, we demonstrate an entirely new PM strategy that capitalizes on strong broad band optical antenna effects in one-dimensional semiconductor nanostructures to dramatically enhance absorption of sunlight. We show that the absorption of sunlight in Si nanowires (Si NWs) can be significantly enhanced over the bulk. The NW's optical properties also naturally give rise to an improved angular response. We propose that by patterning the silicon layer in a thin film PV cell into an array of NWs, one can boost the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250% increase in the light absorption per unit volume of material). These results significantly advance our understanding of the way sunlight is absorbed by one-dimensional semiconductor nanostructures and provide a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach is universal to any semiconductor and a wide range of nanostructures; as such, it provides a new PV platform technology.

  View details for DOI 10.1021/nl9036627

  View details for Web of Science ID 000274338800013

  View details for PubMedID 20078065

• PLASMONICS Electrifying plasmonics on silicon NATURE MATERIALS Hryciw, A., Jun, Y. C., Brongersma, M. L. 2010; 9 (1): 3-4

  View details for DOI 10.1038/nmat2598

  View details for Web of Science ID 000272854800007

  View details for PubMedID 20019659

• Program Committee Photonics for Solar Energy Systems (part of SPIE Photonics Europe) Brongersma, M., L. 2010
• Nanotechnology Research Directions A World Technology Evaluation Center (WTEC) study, Chicago Brongersma, Mark, L., Kekapture, Rohan, D., White, Justin, S., Brongersma, Mark, L. 2010
• Program Committee for the Annual OSA meeting on Integrated Photonics Research Brongersma, M., L. 2010
• Nature Communications Brongersma, Mark, L., Brongersma, Mark, L. 2010
• Active Plasmonic Devices Employing Extreme Light Concentration Gordon Conference on Plasmonics, New Hampshire Brongersma, Mark, L., Sukhdeo, David, S., Kang, J., Petykiewicz, J., Lee, J. H., Jung, W. S. 2010
• Program Chair for the Optical Nanostructures for Photovoltaics (PV) conference Brongersma, M., L. 2010
• Plasmonic, Semiconductor, and Dielectric Building Blocks for Nanophotonics Keynote presentation at the SPIE Annual Meeting, San Diego Brongersma, Mark, L., Chandran, A., Brongersma, Mark, L. 2010
• Recent Advances in Plasmonic Device Technologies Plenary presentation at the Annual Integrated Photonic Research (IPR) conference, Monterey Brongersma, Mark, L., Brongersma, M., L., Polman, A. 2010
• Plasmonics gets transformed Nature Nanotechnology Cai, W., Bell, L., D., Santamore, D., H., Brongersma, M., L., Atwater, H., A. 2010; 5: 485 - 486
• Silicon nanowire hybrid photovoltaics Garnett, E., C., Peters, C., Brongersma, M., Cui, Y., McGehee, M., D. 2010

  View details for DOI 10.1109/PVSC.2010.5614661,000934 - 000938

• Applications: Nanophotonics and Plasmonics WTEC (World Technology Evaluation Center) study on ‘Nanotechnology Research Directions. As the National Nanotechnology Initiative entered into its next decade, WTEC carried out a study to assess the progress made and to anticipate future challenges and opportunities for research in nanotechnology. Hu, E., L., Brongersma, M., L., Baca, A. Springer. 2010: 1
• Plasmonics: A Focus on Light Concentration Keynote presentation at the SPIE Annual Meeting, San Diego Brongersma, Mark, L., Brongersma, M., L., Bell, L., D., Atwater, H., A. 2010
• The Case for Plasmonics Science Brongersma, M. L. 2010; 328: 440-441
• Electrifying plasmonics on silicon Nature Materials Hryciw, A., Coenen, T., Vesseur, Ernst, Jan R., Polman, A., Brongersma, Mark, L. 2010; 9: 3-4
• Plasmonic Solar Cells with Broadband Absorption Enhancements Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Pala, R. A., Barnard, E. S., White, J. S., Brongersma, M. L. IEEE. 2010

  View details for Web of Science ID 000290513603092

• Passive Building Blocks for Plasmonics Nanocircuits with Three-dimensional Slot Waveguides Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Cai, W., Brongersma, M. L. IEEE. 2010

  View details for Web of Science ID 000290513603089

• Plasmonic Solar Cells with Broadband Absorption Enhancements Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Pala, R. A., Barnard, E. S., White, J. S., Brongersma, M. L. IEEE. 2010

  View details for Web of Science ID 000290513602295

• SILICON NANOWIRE HYBRID PHOTOVOLTAICS 35th IEEE Photovoltaic Specialists Conference Garnett, E. C., Peters, C., Brongersma, M., Cui, Y., McGehee, M. IEEE. 2010: 934–938

  View details for Web of Science ID 000287579501035

• Solving Dielectric and Plasmonic Dispersion Equations on a Pocket Calculator Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Kekatpure, R. D., Hryciw, A. C., Barnard, E. S., Brongersma, M. L. IEEE. 2010

  View details for Web of Science ID 000290513602155

• Mid-IR plasmonic antennas on silicon-rich oxinitride absorbing substrates: Nonlinear scaling of resonance wavelengths with antenna length APPLIED PHYSICS LETTERS Sikola, T., Kekatpure, R. D., Barnard, E. S., White, J. S., Van Dorpe, P., Brinek, L., Tomanec, O., Zlamal, J., Lei, D. Y., Sonnefraud, Y., Maier, S. A., Humlicek, J., Brongersma, M. L. 2009; 95 (25)

  View details for DOI 10.1063/1.3278593

  View details for Web of Science ID 000273037700048

• Solving dielectric and plasmonic waveguide dispersion relations on a pocket calculator OPTICS EXPRESS Kekatpure, R. D., Hryciw, A. C., Barnard, E. S., Brongersma, M. L. 2009; 17 (26): 24112-24129

  Abstract

  We present a robust iterative technique for solving complex transcendental dispersion equations routinely encountered in integrated optics. Our method especially befits the multilayer dielectric and plasmonic waveguides forming the basis structures for a host of contemporary nanophotonic devices. The solution algorithm ports seamlessly from the real to the complex domain--i.e., no extra complexity results when dealing with leaky structures or those with material/metal loss. Unlike several existing numerical approaches, our algorithm exhibits markedly-reduced sensitivity to the initial guess and allows for straightforward implementation on a pocket calculator.

  View details for Web of Science ID 000273156200081

  View details for PubMedID 20052123

• General properties of dielectric optical antennas OPTICS EXPRESS Schuller, J. A., Brongersma, M. L. 2009; 17 (26): 24084-24095

  Abstract

  Using Mie theory we derive a number of general results concerning the resonances of spherical and cylindrical dielectric antennas. Specifically, we prove that the peak scattering cross-section of radiation-limited antennas depends only on the resonance frequency and thus is independent of refractive index and size, a result which is valid even when the resonator is atomic-scale. Furthermore, we derive scaling limits for the bandwidth of dielectric antennas and describe a cylindrical mode which is unique in its ability to support extremely large bandwidths even when the particle size is deeply subwavelength. Finally, we show that higher Q antennas may couple more efficiently to an external load, but the optimal absorption cross-section depends only on the resonance frequency.

  View details for Web of Science ID 000273156200078

  View details for PubMedID 20052120

• Compact, High-Speed and Power-Efficient Electrooptic Plasmonic Modulators NANO LETTERS Cai, W., White, J. S., Brongersma, M. L. 2009; 9 (12): 4403-4411

  Abstract

  CMOS compatible electrooptic plasmonic modulators are slated to be key components in chip-scale photonic circuits. In this work, we investigate detailed design and optimization protocols for electrooptic plasmonic modulators that are suitable for free-space coupling and on-chip integration. The metallic structures in the proposed devices offer simultaneous electric and optical functions. The resonance-enhanced nonlinear interaction and submicrometer-footprint of these devices meet the stringent requirements for future CMOS modulators, allowing for high-speed operation (>100 GHz) with a decent modulation depth (>3 dB) and moderate insertion loss (<3 dB) at a very low swing voltage ( approximately 1 V) and power dissipation ( approximately 1 fJ/bit). The realization of the proposed structures appears feasible with current materials and lithographic techniques.

  View details for DOI 10.1021/nl902701b

  View details for Web of Science ID 000272395400077

  View details for PubMedID 19827771

• Optical antenna thermal emitters NATURE PHOTONICS Schuller, J. A., Taubner, T., Brongersma, M. L. 2009; 3 (11): 658-661

  View details for DOI 10.1038/NPHOTON.2009.188

  View details for Web of Science ID 000272302700013

• Near-infrared free-carrier absorption in silicon nanocrystals OPTICS LETTERS Kekatpure, R. D., Brongersma, M. L. 2009; 34 (21): 3397-3399

  Abstract

  We report quantification of the free-carrier absorption (FCA) cross section in silicon nanocrystals embedded in a thin SiO(2) film at 1540 nm using a collinear pump-probe method. To this end, we measured the pump-intensity dependence of both the light transmission through the film and the photoexcited carrier density in the nanocrystals. From these measurements, we extracted a FCA cross section of sigma(FCA)=(3.6+/-1.4)x10(-17) cm(2), consistent with previous results in the visible range and the known lambda(2) scaling behavior of this quantity. Given the rapidly rising prevalence of silicon-based active photonic devices, our finding assumes particular significance for Si-nanocrystal-sensitized rare-earth-atom lasers and all optical switches at important telecom wavelengths.

  View details for Web of Science ID 000271374600050

  View details for PubMedID 19881606

• Side-coupled cavity model for surface plasmon-polariton transmission across a groove OPTICS EXPRESS Liu, J. S., White, J. S., Fan, S., Brongersma, M. L. 2009; 17 (20): 17837-17848

  Abstract

  We demonstrate that the transmission properties of surface plasmon-polaritons (SPPs) across a rectangular groove in a metallic film can be described by an analytical model that treats the groove as a side-coupled cavity to propagating SPPs on the metal surface. The coupling efficiency to the groove is quantified by treating it as a truncated metal-dielectric-metal (MDM) waveguide. Finite-difference frequency-domain (FDFD) simulations and mode orthogonality relations are employed to derive the basic scattering coefficients that describe the interaction between the relevant modes in the system. The modeled SPP transmission and reflection intensities show excellent agreement with full-field simulations over a wide range of groove dimensions, validating this intuitive model. The model predicts the sharp transmission minima that occur whenever an incident SPP resonantly couples to the groove. We also for the first time show the importance of evanescent, reactive MDM SPP modes to the transmission behavior. SPPs that couple to this mode are resonantly enhanced upon reflection from the bottom of the groove, leading to high field intensities and sharp transmission minima across the groove. The resonant behavior exhibited by the grooves has a number of important device applications, including SPP mirrors, filters, and modulators.

  View details for Web of Science ID 000270295300065

  View details for PubMedID 19907571

• Design of Plasmonic Thin-Film Solar Cells with Broadband Absorption Enhancements ADVANCED MATERIALS Pala, R. A., White, J., Barnard, E., Liu, J., Brongersma, M. L. 2009; 21 (34): 3504-?

  View details for DOI 10.1002/adma.200900331

  View details for Web of Science ID 000270380100009

• Engineering light absorption in semiconductor nanowire devices NATURE MATERIALS Cao, L., White, J. S., Park, J., Schuller, J. A., Clemens, B. M., Brongersma, M. L. 2009; 8 (8): 643-647

  Abstract

  The use of quantum and photon confinement has enabled a true revolution in the development of high-performance semiconductor materials and devices. Harnessing these powerful physical effects relies on an ability to design and fashion structures at length scales comparable to the wavelength of electrons (approximately 1 nm) or photons (approximately 1 microm). Unfortunately, many practical optoelectronic devices exhibit intermediate sizes where resonant enhancement effects seem to be insignificant. Here, we show that leaky-mode resonances, which can gently confine light within subwavelength, high-refractive-index semiconductor nanostructures, are ideally suited to enhance and spectrally engineer light absorption in this important size regime. This is illustrated with a series of individual germanium nanowire photodetectors. This notion, together with the ever-increasing control over nanostructure synthesis opens up tremendous opportunities for the realization of a wide range of high-performance, nanowire-based optoelectronic devices, including solar cells, photodetectors, optical modulators and light sources.

  View details for DOI 10.1038/NMAT2477

  View details for Web of Science ID 000268288000016

  View details for PubMedID 19578337

• Nonradiative recombination in strongly interacting silicon nanocrystals embedded in amorphous silicon-oxide films PHYSICAL REVIEW B Rowlette, J. A., Kekatpure, R. D., Panzer, M. A., Brongersma, M. L., Goodson, K. E. 2009; 80 (4)

  View details for DOI 10.1103/PhysRevB.80.045314

  View details for Web of Science ID 000268618100073

• Single crystalline and core-shell indium-catalyzed germanium nanowires-a systematic thermal CVD growth study NANOTECHNOLOGY Xiang, Y., Cao, L., Conesa-Boj, S., Estrade, S., Arbiol, J., Peiro, F., Heiss, M., Zardo, I., Morante, J. R., Brongersma, M. L., Fontcuberta i Morral, A. 2009; 20 (24)

  Abstract

  Germanium nanowires were synthesized using thermal chemical vapor deposition (CVD) and indium as a catalyst. The process parameter space for successful growth was studied. By optimizing the growth temperature and gas pressure, high aspect ratio germanium nanowires have been obtained. Scanning electron microscopy investigations indicate that the final diameter of the nanowires is strongly influenced by the growth temperature and the germane partial pressure. High resolution transmission electron microscopy reveals that nanowires grow either as high quality single crystalline, or with a high quality single-crystalline core and a concentric amorphous shell. The occurrence of these two morphologies is found to only depend on the wire diameter. Chemical analysis of the nanowire tip indicates the presence of indium, validating its role as a catalyst. Raman spectroscopy measurements reveal a higher incidence of core-shell structures for nanowires synthesized at 30 Torr and indicate the presence of tensile strain. These results are important towards obtaining high quality germanium nanowires without the use of gold as a catalyst, which is known to degrade the wires' electrical and optical properties.

  View details for DOI 10.1088/0957-4484/20/24/245608

  View details for Web of Science ID 000266436500024

  View details for PubMedID 19471084

• Energy transfer in nanowire solar cells with photon-harvesting shells Peters, C. H., Guichard, A. R., Hryciw, A. C., Brongersma, M. L., McGehee, M. D. AMER INST PHYSICS. 2009

  View details for DOI 10.1063/1.3153281

  View details for Web of Science ID 000267599600137

• Broadband enhancement of light emission in silicon slot waveguides OPTICS EXPRESS Jun, Y. C., Briggs, R. M., Atwater, H. A., Brongersma, M. L. 2009; 17 (9): 7479-7490

  Abstract

  We investigate the light emission properties of electrical dipole emitters inside 2-dimensional (2D) and 3-dimensional (3D) silicon slot waveguides and evaluate the spontaneous emission enhancement (F(p)) and waveguide coupling ratio (beta). Under realistic conditions, we find that greater than 10-fold enhancement in F(p) can be achieved, together with a beta as large as 0.95. In contrast to the case of high Q optical resonators, such performance enhancements are obtained over a broad wavelength region, which can cover the entire emission spectrum of popular optical dopants such as Er. The enhanced luminescence efficiency and the strong coupling into a limited set of well-defined waveguide modes enables a new class of power-efficient, CMOS-compatible, waveguide-based light sources.

  View details for Web of Science ID 000266381700063

  View details for PubMedID 19399126

• Synthesis parameter space of bismuth catalyzed germanium nanowires APPLIED PHYSICS LETTERS Xiang, Y., Cao, L., Arbiol, J., Brongersma, M. L., Fontcuberta i Morral, A. 2009; 94 (16)

  View details for DOI 10.1063/1.3116625

  View details for Web of Science ID 000265823300056

• Metal-dielectric-metal plasmonic waveguide devices for manipulating light at the nanoscale CHINESE OPTICS LETTERS Veronis, G., Yu, Z., Kocabas, S. E., Miller, D. A., Brongersma, M. L., Fang, S. 2009; 7 (4): 302-308

  View details for DOI 10.3788/COL20090704.0302

  View details for Web of Science ID 000266970900011

• Extraordinary optical absorption through subwavelength slits OPTICS LETTERS White, J. S., Veronis, G., Yu, Z., Barnard, E. S., Chandran, A., Fan, S., Brongersma, M. L. 2009; 34 (5): 686-688

  Abstract

  We report on the ability of resonant plasmonic slits to efficiently concentrate electromagnetic energy into a nanoscale volume of absorbing material placed inside or directly behind the slit. This gives rise to extraordinary optical absorption characterized by an absorption enhancement factor that well exceeds the enhancements seen for extraordinary optical transmission through slits. A semianalytic Fabry-Perot model for the resonant absorption is developed and shown to quantitatively agree with full-field simulations. We show that absorption enhancements of nearly 1000% can be realized at 633 nm for slits in aluminum films filled with silicon. This effect can be utilized in a wide range of applications, including high-speed photodetectors, optical lithography and recording, and biosensors.

  View details for Web of Science ID 000264522400046

  View details for PubMedID 19252593

• Plasmon-enhanced emission from optically-doped MOS light sources OPTICS EXPRESS Hryciw, A. C., Jun, Y. C., Brongersma, M. L. 2009; 17 (1): 185-192

  Abstract

  We evaluate the spontaneous emission rate (Purcell) enhancement for optically-doped metal-dielectric-semiconductor light-emitting structures by considering the behavior of a semiclassical oscillating point dipole placed within the dielectric layer. For a Ag-SiO(2)-Si structure containing emitters at the center of a 20-nm-thick SiO(2) layer, spontaneous emission rate enhancements of 40 to 60 can be reached in the wavelength range of 600 to 1800 nm, far away from the surface plasmon resonance; similar enhancements are also possible if Al is used instead of Ag. For dipoles contained in the thin oxide layer of a Ag-SiO(2)-Si-SiO(2) structure, the emission exhibits strong preferential coupling to a single well-defined Si waveguide mode. This work suggests a means of designing a new class of power-efficient, high-modulation-speed, CMOS-compatible optical sources that take full advantage of the excellent electrical properties and plasmon-enhanced op cal properties afforded by MOS devices.

  View details for Web of Science ID 000262220300021

  View details for PubMedID 19129887

• Planar Lenses Based on Nanoscale Slit Arrays in a Metallic Film NANO LETTERS Verslegers, L., Catrysse, P. B., Yu, Z., White, J. S., Barnard, E. S., Brongersma, M. L., Fan, S. 2009; 9 (1): 235-238

  Abstract

  We experimentally demonstrate planar lenses based on nanoscale slit arrays in a metallic film. Our lens structures consist of optically thick gold films with micron-size arrays of closely spaced, nanoscale slits of varying widths milled using a focused ion beam. We find excellent agreement between electromagnetic simulations of the design and confocal measurements on manufactured structures. We provide guidelines for lens design and show how actual lens behavior deviates from simple theory.

  View details for DOI 10.1021/nl802830y

  View details for Web of Science ID 000262519100044

  View details for PubMedID 19053795

• NANOPLASMONICS: COMPONENTS, DEVICES, AND CIRCUITS PLASMONIC NANOGUIDES AND CIRCUITS Brongersma, M. L., Schuller, J. A., White, J., Jun, Y., Bozhevolnyi, S. I., Sondergaard, T., Zia, R., Bozhevolnyi, S. I. 2009: 405–38

  View details for Web of Science ID 000289061900014

• Plasmonics, Light Localization, and Metamaterials Brongersma, M., L. 2009
• Nanoplasmonics Tutorial given at the open house of the center of optical technologies at Lehigh University Brongersma, Mark, L., Jun, Y. C., Brongersma, Mark, L. 2009
• Nanoplasmonics: Components, Devices, and Circuits Plasmonic Nanoguides and Circuits Brongersma, Mark, L., Schuller, Jon, A., White, J., Jun, Y. C., Bozhevolnyi, Sergey, I., Søndergaard, T. edited by Bozhevolnyi, S. I. World Scientific. 2009: 1
• Materials Research Society Symposium Proceedings edited by Negro, L., Dal, Brongersma, M., L. 2009
• Program Committee Surface Plasmon Photonics (SPP) 4 Brongersma, M., L. 2009
• Guest Editor for Plasmonics and Metamaterials issue for the Journal of the Optical Society of America Brongersma, Mark, L., Barnard, E., Cai, W., Jun, Y. C., White, J., Brongersma, Mark, L. 2009
• Active Plasmonics Ultrafast Developments Nature Photonics Cao, L., Zeltzer, G., Ruiz, R., Thomann, I., Lee, H., Brongersma, Mark, L. 2009; 12: 3
• Plasmonics: The Next Wave of Chipscale Technologies Brongersma, M., L. 2009
• Program Committee Near-Field Optics (NFO10) Conference Brongersma, M., L. 2009
• Program Committee Nanometa-2009 Brongersma, M., L. 2009
• Plasmonics and Metamaterials: Introduction J. Opt. Soc. Am. B26, PM1 Boardman, A., Bell, L., D., Brongersma, M., L., Atwater, H., A. 2009; B26, PM1
• Plasmonics Short course at the Conference on Lasers and Electro-optics CLEO Europe, Munich, Germany Brongersma, Mark, L., Zia, R., Yanik, M., F., Fan, S., Brongersma, M., L. 2009
• Planar Lenses Based on Nanoscale Slit Arrays in a Metallic Film Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Verslegers, L., Catrysse, P. B., Yu, Z., White, J. S., Barnard, E. S., Brongersma, M. L., Fan, S. IEEE. 2009: 3224–3225

  View details for Web of Science ID 000274751302598

• Ultrafast developments NATURE PHOTONICS Cao, L., Brongersma, M. L. 2009; 3 (1): 12-13

  View details for DOI 10.1038/nphoton.2008.259

  View details for Web of Science ID 000262394500007

• Temperature-dependent Auger recombination dynamics in luminescent silicon nanowires PHYSICAL REVIEW B Guichard, A. R., Kekatpure, R. D., Brongersma, M. L., Kamins, T. I. 2008; 78 (23)

  View details for DOI 10.1103/PhysRevB.78.235422

  View details for Web of Science ID 000262245400108

• Quantification of Free-Carrier Absorption in Silicon Nanocrystals with an Optical Microcavity NANO LETTERS Kekatpure, R. D., Brongersma, M. L. 2008; 8 (11): 3787-3793

  Abstract

  We present a highly sensitive and accurate microcavity-based technique to quantify the free-carrier absorption (FCA) cross-section of semiconductor quantum-dot ensembles. The procedure is based on measuring the pump-intensity-dependent broadening of the whispering gallery modes (WGMs) of microdisk resonators. We have applied this technique to determine the FCA cross-section of Si nanocrystals (Si-ncs) in the visible-near-infrared wavelength range. Our procedure accounts for the size distribution effects by including the measured wavelength dependence of the excitation cross-section and the decay rate of photoexcited carriers in the analysis. By monitoring the WGM widths at various wavelengths in the 700-900 nm wavelength range, we found that the FCA cross-section follows an approximately quadratic wavelength dependence. The magnitude of the FCA cross-section of Si nanocrystals was determined to be a factor of 7 higher than that in bulk Si. For this reason, these findings have important implications for the design of Si-based lasers and all-optical switching devices in which FCA plays a critical role.

  View details for DOI 10.1021/nl8021016

  View details for Web of Science ID 000260888600042

  View details for PubMedID 18826288

• Spectral properties of plasmonic resonator antennas OPTICS EXPRESS Barnard, E. S., White, J. S., Chandran, A., Brongersma, M. L. 2008; 16 (21): 16529-16537

  Abstract

  A theoretical study of the optical properties of metallic nano-strip antennas is presented. Such strips exhibit retardation-based resonances resulting from the constructive interference of counter propagating short-range surface plasmon-polaritons (SR-SPPs) that reflect from the antenna terminations. A Fabry-P erot model was formulated that successfully predicts both the peak position and spectral shape of their optical resonances. This model requires knowledge of the SR-SPP reflection amplitude and phase pickup upon reflection from the structure terminations. These quantities were first estimated using an intuitive Fresnel reflection model and then calculated exactly using full-field simulations based on the finite-difference frequency-domain (FDFD) method. With only three dimensionless scaling parameters, the Fabry-P erot model provides simple design rules for engineering resonant properties of such plasmonic resonator antennas.

  View details for Web of Science ID 000260864900028

  View details for PubMedID 18852761

• Nonresonant enhancement of spontaneous emission in metal-dielectric-metal plasmon waveguide structures PHYSICAL REVIEW B Jun, Y. C., Kekatpure, R. D., White, J. S., Brongersma, M. L. 2008; 78 (15)

  View details for DOI 10.1103/PhysRevB.78.153111

  View details for Web of Science ID 000260574400012

• Fundamental photophysics and optical loss processes in Si-nanocrystal-doped microdisk resonators PHYSICAL REVIEW A Kekatpure, R. D., Brongersma, M. L. 2008; 78 (2)

  View details for DOI 10.1103/PhysRevA.78.023829

  View details for Web of Science ID 000259263500079

• Plasmonics - Engineering optical nanoantennas NATURE PHOTONICS Brongersma, M. L. 2008; 2 (5): 270-272

  View details for DOI 10.1038/nphoton.2008.60

  View details for Web of Science ID 000256077900007

• A nonvolatile plasmonic switch employing photochromic molecules NANO LETTERS Pala, R. A., Shimizu, K. T., Melosh, N. A., Brongersma, M. L. 2008; 8 (5): 1506-1510

  Abstract

  We demonstrate a surface plasmon-polariton (SPP) waveguide all-optical switch that combines the unique physical properties of small molecules and metallic (plasmonic) nanostructures. The switch consists of a pair of gratings defined in an aluminum film coated with a 65 nm thick layer of photochromic (PC) molecules. The first grating couples a signal beam consisting of free space photons to SPPs that interact effectively with the PC molecules. These molecules can reversibly be switched between transparent and absorbing states using a free space optical pump. In the transparent (signal "on") state, the SPPs freely propagate through the molecular layer, and in the absorbing (signal "off") state, the SPPs are strongly attenuated. The second grating serves to decouple the SPPs back into a free space optical beam, enabling measurement of the modulated signal with a far-field detector. In a preliminary study, the switching behavior of the PC molecules themselves was confirmed and quantified by surface plasmon resonance spectroscopy. The excellent (16%) overlap of the SPP mode profile with the thin layer of switching molecules enabled efficient switching with power densities of approximately 6.0 mW/cm2 in 1.5 microm x 8 microm devices, resulting in plasmonic switching powers of 0.72 nW per device. Calculations further showed that modulation depths in access of 20 dB can easily be attained in optimized designs. The quantitative experimental and theoretical analysis of the nonvolatile switching behavior in this letter guides the design of future nanoscale optically or electrically pumped optical switches.

  View details for DOI 10.1021/nl0808839

  View details for Web of Science ID 000255906400042

  View details for PubMedID 18412401

• Gain-induced switching in metal-dielectric-metal plasmonic waveguides APPLIED PHYSICS LETTERS Yu, Z., Veronis, G., Fan, S., Brongersma, M. L. 2008; 92 (4)

  View details for DOI 10.1063/1.2839324

  View details for Web of Science ID 000252860400017

• Recent Progress in Plasmonics Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Brongersma, M. L. IEEE. 2008: 3417–3418

  View details for Web of Science ID 000260498401702

• Gain-induced switching in metal-dielectric-metal plasmonic waveguides Yu, Z., Veronis, G., Brongersma, M. L., Fan, S., Greiner, C. M., Waechter, C. A. SPIE-INT SOC OPTICAL ENGINEERING. 2008

  View details for DOI 10.1117/12.764052

  View details for Web of Science ID 000254226600016

• Active plasmonic components employing extreme light concentration 487, 21st Annual Meeting of the IEEE Lasers and Electro-Optics Society Brongersma, Mark, L., Cai, W., Catrysse, Peter, B. 2008; 487
• The dependence of poly-crystalline SiC mid-infrared optical properties on deposition conditions Provine, J., Roper, C., Schuller, J., A., Brongersma, M., L., Maboudian, R., Howe, R., T. 2008
• Fundamental photophysics and optical loss processes in Si-nanocrystal doped microcavities Phys. Rev. Kekatpure, Rohan, D., Shin, W., Fan, S., Brongersma, Mark, L. 2008; A 78: 23829
• Free-carrier absorption in Si nanocrystals probed by microcavity photoluminescence Kekatpure, R., D., Guichard, A., R., Brongersma, M., L. 2008
• Nanoplasmonics tutorial at the Materials Research Society (MRS) Spring Meeting, San Francisco Brongersma, Mark, L., Kekatpure, Rohan, D., Brongersma, Mark, L., Kamins, Theodore, I. 2008
• Plasmonics Bridging the Gap Between Microphotonics and Nanoelectronics Brongersma, M., L. 2008
• Photophysics of Si nanostructures: ensembles and single particles Guichard, A., R., Kekatpure, R., D., Brongersma, M., L. 2008
• Gain-induced switching in metal-dielectric-metal plasmonic waveguides Yu, Z., Veronis, G., Brongersma, M., L., Fan, S. 2008
• The Dependence of Poly-crystalline SiC Mid-Infrared Optical Properties on Deposition Conditions IEEE/LEOS International Conference on Optical MEMS and Nanophotonics Provine, J., Roper, C., Schuller, J. A., Brongersma, M. L., Maboudian, R., Howe, R. T. IEEE. 2008: 182–183

  View details for Web of Science ID 000264556700092

• Photophysics of Si nanostructures: ensembles and single particles Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Guichard, A. R., Kekatpure, R. D., Brongersma, M. L. IEEE. 2008: 1331–1332

  View details for Web of Science ID 000260498400668

• Free-carrier Absorption in Si Nanocrystals Probed by Microcavity Photoluminescence Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Kekatpure, R. D., Guichard, A. R., Brongersma, M. L. IEEE. 2008: 1495–1496

  View details for Web of Science ID 000260498400750

• Plasmon-assisted local temperature control to pattern individual semiconductor nanowires and carbon nanotubes NANO LETTERS Cao, L., Barsic, D. N., Guichard, A. R., Brongersma, M. L. 2007; 7 (11): 3523-3527

  Abstract

  We demonstrate a new versatile strategy to rapidly heat and cool subdiffraction-limited volumes of material with a focused light beam. The local temperature rise is obtained by exploiting the unique optical properties of metallic nanostructures that facilitate efficient light-to-heat conversion through the excitation of surface plasmons (collective electron oscillations). By locally heating nanoscale metallic catalysts, growth of semiconductor nanowires and carbon nanotubes can be initiated and controlled at arbitrarily prespecified locations and down to the single nanostructure level in a room-temperature chamber. This local heating strategy can be orders of magnitude (>10(5)) more energy efficient than conventional chemical vapor deposition (CVD) tools in which an entire chamber/substrate is heated. For these reasons, it has great potential for use in process- and energy-efficient assembly of nanowires into complementary metal-oxide-semiconductor (CMOS) compatible device architectures. In general, the high degree of spatial and temporal control over nanoscale thermal environments afforded by this method inspires new pathways for manipulating a range of important thermally stimulated processes and the development of novel photothermal devices.

  View details for DOI 10.1021/nl0722370

  View details for Web of Science ID 000251059800049

  View details for PubMedID 17963415

• Plasmonics - the missing link between nanoelectronics and microphotonics APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Brongersma, M. L., Zia, R., Schuller, J. A. 2007; 89 (2): 221-223

  View details for DOI 10.1007/s00339-007-4151-1

  View details for Web of Science ID 000249016500001

• Dielectric metamaterials based on electric and magnetic resonances of silicon carbide particles PHYSICAL REVIEW LETTERS Schuller, J. A., Zia, R., Taubner, T., Brongersma, M. L. 2007; 99 (10)

  Abstract

  Silicon carbide particles exhibit both electric and magnetic optical resonances, allowing unexplored dielectric metamaterial designs. Experimental extinction spectra and Mie theory calculations of single microscale rod-shaped particles reveal three observable midinfrared resonant modes. Two of the modes are degenerate, with a frequency that can be tuned according to a resonance condition derived within the Letter. The existence of both electric and magnetic resonances may enable a novel negative refractive index metamaterial design.

  View details for DOI 10.1103/PhysRevLett.99.107401

  View details for Web of Science ID 000249324100031

  View details for PubMedID 17930407

• Surface plasmon polariton analogue to Young's double-slit experiment NATURE NANOTECHNOLOGY Zia, R., Brongersma, M. L. 2007; 2 (7): 426-429

  Abstract

  When a light wave strikes a metal film it can, under appropriate conditions, excite a surface plasmon polariton (SPP)--a surface electromagnetic wave that is coupled to the free electrons in the metal. Such SPPs are involved in a wide range of phenomena, including nanoscale optical waveguiding, perfect lensing, extraordinary optical transmission, subwavelength lithography and ultrahigh-sensitivity biosensing. However, before the full potential of technology based on SPPs (termed 'plasmonics') can be realized, many fundamental questions regarding the interaction between light and matter at the nanoscale need to be answered. For over 200 years, Young's double-slit experiment has been a valuable pedagogical tool for demonstrating the wave nature of light. Here, we perform a double-slit experiment with SPPs to reveal the strong analogy between SPP propagation along the surface of metallic structures and light propagation in conventional dielectric components (such as glass waveguides). This allows us to construct a general framework to describe the propagation, diffraction and interference of SPPs. It also suggests that there is an effective diffraction limit for the lateral confinement of SPPs on metal stripe waveguides, and justifies the use of well-developed concepts from conventional optics and photonics in the design of new plasmonic devices.

  View details for DOI 10.1038/nnano.2007.185

  View details for Web of Science ID 000248302500013

  View details for PubMedID 18654327

• Metal-dielectric slot-waveguide structures for the propagation of surface plasmon polaritons at 1.55 mu m IEEE JOURNAL OF QUANTUM ELECTRONICS Feng, N., Brongersma, M. L., Dal Negro, L. 2007; 43 (5-6): 479-485

  View details for DOI 10.1109/JQE.2007.897913

  View details for Web of Science ID 000246894300018

• Omnidirectional light emission via surface plasmon polaritons APPLIED PHYSICS LETTERS Liu, J. S., Brongersma, M. L. 2007; 90 (9)

  View details for DOI 10.1063/1.2437053

  View details for Web of Science ID 000244591700016

• Thin film patterning by surface-plasmon-induced thermocapillarity APPLIED PHYSICS LETTERS Roentzsch, L., Heinig, K., Schuller, J. A., Brongersma, M. L. 2007; 90 (4)

  View details for DOI 10.1063/1.2432282

  View details for Web of Science ID 000243789600122

• High Q/V microdisk resonators for observation of Purcell effect in silicon nanocrystals 4th IEEE International Conference on Group IV Photonics Kekatpure, R. D., Guichard, A. R., Brongersma, M. L. IEEE. 2007: 259–261

  View details for Web of Science ID 000253465500087

• DEVELOPMENT AND NEAR-FIELD CHARACTERIZATION OF SURFACE PLASMON WAVEGUIDES SURFACE PLASMON NANOPHOTONICS Weeber, J., Baudrion, A., Gonzalez, M. U., Dereux, A., Zia, R., Brongersma, M. L., Brongersma, M. L., Kik, P. G. 2007; 131: 39–54

  View details for DOI 10.1007/978-1-4020-4333-8_4

  View details for Web of Science ID 000288851900005

• SURFACE PLASMON NANOPHOTONICS SURFACE PLASMON NANOPHOTONICS Kik, P. G., Brongersma, M. L., Brongersma, M. L., Kik, P. G. 2007; 131: 1–9

  View details for DOI 10.1007/978-1-4020-4333-8_1

  View details for Web of Science ID 000288851900002

• Auger recombination in luminescent, CMOS-compatible Si nanowires Guichard, A., R., Kekatpure, R., D., Brongersma, M., L. 2007
• Development and Near-field Characterization of Surface Plasmon Waveguides Surface Plasmon Nanophotonics Weeber, J., C., Baudrion, A., L, González, M., U., Dereux, A., Zia, R., Brongersma, Mark, L. edited by Brongersma, Mark, L., Kik, Pieter, G. 2007: 271
• Excitons and Plasmon Resonances in Nanostructures - Fundamentals, synthesis, and applications Brongersma, M., L. 2007
• Metal-dielectric slot waveguide structures for the propagation of surface plasmon polaritons at 1.55 µm IEEE Journ. Of Quant. Electron. Feng, N., White, Justin, S., Fan, S., Brongersma, Mark, L. 2007; 43: 479- 485
• High Q/V microdisk resonators for observation of purcell effect in silicon nanocrystals Kekatpure, R., D., Guichard, A., R., Brongersma, M., L. 2007
• Surface Plasmon Nanophotonics Surface Plasmon Nanophotonics Kik, Pieter, G., Brongersma, Mark, L. edited by Brongersma, Mark, L., Kik, Pieter, G. 2007: 271
• Plasmonics – A New Wave of Opportunities Briefing of National Academies Committee on Nanophotonics Accessibility and Applicability, Washington DC Brongersma, Mark, L., Brongersma, M., L., Kik, P., G., Atwater, H., A. 2007
• Midinfrared Dielectric Metamaterials Based on Electric and Magnetic Mie Resonances of Silicon Carbide Particles Phys. Rev. Lett. Schuller, J., A., Guichard, A., R., Hryciw, A., C., Brongersma, M., L., McGehee, M., D. 2007; 99: 107401
• Design of mid-infrared photodetectors enhanced by surface plasmons on grating structures Yu, Z., Veronis, G., Brongersma, M., L., Fan, S. 2007
• Scientific Advisory Board for the journal "Metamaterials" Brongersma, Mark, L., Polman, A., Min, K., S., Boer, E., Tambo, T., Atwater, H., A. 2007
• Plasmonics – The Next Wave of Chipscale Technologies NanoMaterials for Defense Applications Symposium, Organized by the US Denfense Agencies, San Diego Brongersma, Mark, L., Brongersma, M., L., Kik, P., G., Meltzer, S., Requicha, A., A.G., Atwater, H., A. 2007
• Chipscale Plasmonics and Nanophotonics DARPA Components from Metamaterials Workshop, Washington Brongersma, Mark, L., Seo, M., Huo, Y., Sarmiento, T., Harris, James, S., Brongersma, Mark, L. 2007
• Plasmonics - The missing link between nanoelectronics and microphotonics Progress in Electromagnetics Research Symposium (PIERS 2007) Brongersma, M. L., Zia, R., Schuler, J. ELECTROMAGNETICS ACAD. 2007: 1043–1045

  View details for Web of Science ID 000246922600230

• Design of mid-infrared photodetectors enhanced by surface plasmons on grating structures Conference on Integrated Optics - Devices, Materials, and Technology XI Yu, Z., Veronis, G., Brongersma, M. L., Fan, S. SPIE-INT SOC OPTICAL ENGINEERING. 2007

  View details for DOI 10.1117/12.698016

  View details for Web of Science ID 000246061700022

• Auger recombination in luminescent, CMOS-compatible Si nanowires 4th IEEE International Conference on Group IV Photonics Guichard, A. R., Kekatpure, R. D., Brongersma, M. L. IEEE. 2007: 250–252

  View details for Web of Science ID 000253465500084

• Probing molecular junctions using surface plasmon resonance spectroscopy NANO LETTERS Shimizu, K. T., Pala, R. A., Fabbri, J. D., Brongersma, M. L., Melosh, N. A. 2006; 6 (12): 2797-2803

  Abstract

  The optical absorption spectra of nanometer-thick organic films and molecular monolayers sandwiched between two metal contacts have been measured successfully using surface plasmon resonance spectroscopy (SPRS). The electric field within metal-insulator (organic)-metal (MIM) cross-bar junctions created by surface plasmon-polaritons excited on the metal surface allows sensitive measurement of molecular optical properties. Specifically, this spectroscopic technique extracts the real and imaginary indices of the organic layer for each wavelength of interest. The SPRS sensitivity was calculated for several device architectures, metals, and layer thicknesses to optimize the organic film absorptivity measurements. Distinct optical absorption features were clearly observed for R6G layers as thin as a single molecular monolayer between two metal electrodes. This method also enables dynamic measurement of molecular conformation inside metallic junctions, as shown by following the optical switching of a thin spiropyran/polymer film upon exposure to UV light. Finally, optical and electrical measurements can be made simultaneously to study the effect of electrical bias and current on molecular conformation, which may have significant impact in areas such as molecular and organic electronics.

  View details for DOI 10.1021/nl061893h

  View details for Web of Science ID 000242786500029

  View details for PubMedID 17163708

• Plasmon-assisted chemical vapor deposition NANO LETTERS Boyd, D. A., Greengard, L., Brongersma, M., El-Naggar, M. Y., Goodwin, D. G. 2006; 6 (11): 2592-2597

  Abstract

  We introduce a new chemical vapor deposition (CVD) process that can be used to selectively deposit materials of many different types. The technique makes use of the plasmon resonance in nanoscale metal structures to produce the local heating necessary to initiate deposition when illuminated by a focused low-power laser. We demonstrate the technique, which we refer to as plasmon-assisted CVD (PACVD), by patterning the spatial deposition of PbO and TiO(2) on glass substrates coated with a dispersion of 23 nm gold particles. The morphology of both oxide deposits is consistent with local laser-induced heating of the gold particles by more than 150 degrees C. We show that temperature changes of this magnitude are consistent with our analysis of the heat-loss mechanisms. The technique is general and can be used to spatially control the deposition of virtually any material for which a CVD process exists.

  View details for DOI 10.1021/nl062061m

  View details for Web of Science ID 000241856700036

  View details for PubMedID 17090097

• Cavity Q measurements of silica microspheres with nanocluster silicon active layer IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Sung, J., Tewary, A., Brongersma, M. L., Shin, J. H. 2006; 12 (6): 1388-1393

  View details for DOI 10.1109/JSTQE.2006.885631

  View details for Web of Science ID 000243013700011

• Silicon-nanocrystal-coated silica microsphere thermooptical switch IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Tewary, A., Digonnet, M. J., Sung, J., Shin, J. H., Brongersma, M. L. 2006; 12 (6): 1476-1479

  View details for DOI 10.1109/JSTQE.2006.885389

  View details for Web of Science ID 000243013700020

• Design of midinfrared photodetectors enhanced by surface plasmons on grating structures APPLIED PHYSICS LETTERS Yu, Z., Veronis, G., Fan, S., Brongersma, M. L. 2006; 89 (15)

  View details for DOI 10.1063/1.2360896

  View details for Web of Science ID 000241247900016

• Near-field characterization of guided polariton propagation and cutoff in surface plasmon waveguides PHYSICAL REVIEW B Zia, R., Schuller, J. A., Brongersma, M. L. 2006; 74 (16)

  View details for DOI 10.1103/PhysRevB.74.165415

  View details for Web of Science ID 000241723700101

• Tunable light emission from quantum-confined excitons in TiSi2-catalyzed silicon nanowires NANO LETTERS Guichard, A. R., Barsic, D. N., Sharma, S., Kamins, T. I., Brongersma, M. L. 2006; 6 (9): 2140-2144

  Abstract

  Visible and near-infrared photoluminescence (PL) at room temperature is reported from Si nanowires (NWs) grown by chemical vapor deposition from TiSi2 catalyst sites. NWs grown with average diameter of 20 nm were etched and oxidized to thin and passivate the wires. The PL emission blue shifted continuously with decreasing nanowire diameter. Slowed oxidation was observed for small nanowire diameters and provides a high degree of control over the emission wavelength. Transmission electron microscopy, PL, and time-resolved PL data are fully consistent with quantum confinement of charge carriers in the Si nanowire core being the source of luminescence. These light emitting nanowires could find application in future CMOS-compatible photonic devices.

  View details for DOI 10.1021/nl061287m

  View details for Web of Science ID 000240465100054

  View details for PubMedID 16968040

• Plasmonics: the next chip-scale technology MATERIALS TODAY Zia, R., Schuller, J. A., Chandran, A., Brongersma, M. L. 2006; 9 (7-8): 20-27

  View details for Web of Science ID 000242622700019

• Controlling defect and Si nanoparticle luminescence from silicon oxynitride films with CO2 laser annealing APPLIED PHYSICS LETTERS Tewary, A., Kekatpure, R. D., Brongersma, M. L. 2006; 88 (9)

  View details for DOI 10.1063/1.2178769

  View details for Web of Science ID 000235736300080

• Erbium-implanted silica microsphere laser 14th International Conference on Ion Beam Modification of Materials (IBMM 2004) Kalkman, J., Polman, A., Kippenberg, T. J., Vahala, K. J., Brongersma, M. L. ELSEVIER SCIENCE BV. 2006: 182–85

  View details for DOI 10.1016/j.nimb.2005.08.160

  View details for Web of Science ID 000236225200049

• Synthesis and optimization of luminescent Si nanoparticles by CO2 laser annealing and Si nanocrystal light emission in microcavities Kekatpure, R., D., Tewary, A., Brongersma, M., L. 2006
• Guiding Properties of Surface Plasmon-Polariton Waveguides "Nanophotonics with Surface Plasmons” and part of a Elsevier Series on “Advances in Nano-Optics and Nano-Photonics”. Zia, R., Brongersma, M. edited by Shalaev, V., Kawata, S. 2006: 1
• Light emitting silicon nanowires for photonic device applications Guichard, A., R., Brongersma, M., L., Kamins, T., Sharma, S. 2006
• Silicon-nanocrystal-coated Silica Microsphere Thermooptical Switch Tewary, A., Digonnet, Michel, J. F., Brongersma, Mark., L., Sung, J., Shin, Jung, H. 2006
• Silicon-Based Microphotonics Brongersma, M., L. 2006
• Synthesis and optimization of luminescent Si nanoparticles by CO2 laser annealing and Si nanocrystal light emission in microcavities Kekatpure, Rohan, D., Tewary, A., Brongersma, Mark., L. 2006
• High-Q whispering gallery modes in wet etched silica microdisk resonators containing silicon nanocrystals Kekatpure, R., D., Brongersma, M., L. 2006
• Plasmon AccessScience@McGraw-Hill, http://www.accessscience.com Brongersma, Mark, L., Veronis, G., Fan, S., Brongersma, Mark, L. 2006

  View details for DOI 10.1036/1097-8542.526250

• Synthesis and optimization of luminescent Si nanoparticles by CO2 laser annealing and Si nanocrystal light emission in microcavities Conference on Optoelectronic Devices - Physics, Fabrication, and Application III Kekatpure, R. D., Tewary, A., Brongersma, M. L. SPIE-INT SOC OPTICAL ENGINEERING. 2006

  View details for DOI 10.1117/12.686562

  View details for Web of Science ID 000243902000001

• Light emitting silicon nanowires for photonic device applications 3rd International Conference on Group IV Photonics Guichard, A. R., Brongersma, M. L., Kamins, T., Sharma, S. IEEE. 2006: 137–139

  View details for Web of Science ID 000244096100047

• Silicon-nanocrystal-coated silica microsphere then-nooptical switch Conference on Silicon Photonics Tewary, A., Digonnet, M. J., Brongersma, M. L. SPIE-INT SOC OPTICAL ENGINEERING. 2006

  View details for DOI 10.1117/12.669392

  View details for Web of Science ID 000237274900023

• High-Q whispering gallery modes in wet etched silica microdisk resonators containing silicon nanocrystals 3rd International Conference on Group IV Photonics Kekatpure, R. D., Brongersma, M. L. IEEE. 2006: 22–24

  View details for Web of Science ID 000244096100008

• Design of a silicon-based field-effect electro-optic modulator with enhanced light-charge interaction OPTICS LETTERS Kekatpure, R. D., Brongersma, M. L., Shenoy, R. S. 2005; 30 (16): 2149-2151

  Abstract

  A new design for an all-silicon field-effect optical modulator in a ring resonator geometry is proposed and modeled by means of finite-element method simulations. It is shown that the optimal relative placement of the ultrathin field-effect-generated charge layers and the optical mode in the strong-confinement waveguides leads to more than an order-of-magnitude enhancement in the light-charge interaction compared with the recent predictions in the literature. We show that such an enhancement could provide optical modulation with a >7 dB extinction-ratio using a voltage swing of only 2 V, thus making our design compatible with complementary metal-oxide semiconductor technology.

  View details for Web of Science ID 000231072700033

  View details for PubMedID 16127939

• Nanoengineered silicon/silicon dioxide nanoparticle heterostructures SOLID STATE SCIENCES Ostraat, M. L., Brongersma, M., Atwater, H. A., Flagan, R. C. 2005; 7 (7): 882-890

  View details for DOI 10.1016/j.solidstatesubstances.2005.01.019

  View details for Web of Science ID 000230259500009

• Dielectric waveguide model for guided surface polaritons OPTICS LETTERS Zia, R., Chandran, A., Brongersma, M. L. 2005; 30 (12): 1473-1475

  Abstract

  Although surface polariton modes supported by finite-width interfaces can guide electromagnetic energy in three dimensions, we demonstrate for the first time to our knowledge that such modes can be modeled by the solutions of two-dimensional dielectric slab waveguides. An approximate model is derived by a ray-optics interpretation that is consistent with previous investigations of the Fresnel relations for surface polariton reflection. This model is compared with modal solutions for metal stripe waveguides obtained by full vectorial magnetic-field finite-difference methods. The field-symmetric modes of such waveguides are shown to be in agreement with the normalized dispersion relationship for analogous TE modes of dielectric slab waveguides. Lateral confinement is investigated by comparison of power-density profiles, and implications for the diffraction limit of guided polariton modes are discussed.

  View details for Web of Science ID 000229689400015

  View details for PubMedID 16007778

• Leaky and bound modes of surface plasmon waveguides PHYSICAL REVIEW B Zia, R., Selker, M. D., Brongersma, M. L. 2005; 71 (16)

  View details for DOI 10.1103/PhysRevB.71.165431

  View details for Web of Science ID 000228763100117

• Microring and microdisk optical resonators using silicon nanocrystals and erbium prepared using silicon technology Symposium of the European-Materials-Research-Society on Si-Based Photonics - Towards True Monolithic Integration Gardner, D. S., Brongersma, M. L. ELSEVIER SCIENCE BV. 2005: 804–11

  View details for DOI 10.1016/j.optmat.2004.08.017

  View details for Web of Science ID 000227621300015

• Sub-wavelength resonances in metal-dielectric-metal plasmonic structures 18th Annual Meeting of the IEEE-Lasers-and-Electro-Optical-Society Fan, S. H., Shin, H., Brongersma, M., Veronis, G., Shen, J. T., Catrysse, P. B. IEEE. 2005: 520–521

  View details for Web of Science ID 000235109700263

• Evidence for stimulated emission in silicon nanocrystal microspheres 2nd IEEE International Conference on Group IV Photonics Chen, H., Sung, J. Y., Tewary, A., Brongersma, M., Shin, J. H., Fauchet, P. M. IEEE. 2005: 99–101

  View details for Web of Science ID 000234323300036

• Sub-wavelength resonances in metal-dielectric-metal plasmonic structures Fan, S. 2005
• Plasmonics--Nanoscale Optics and Photonics Based on Metals Brongersma, M., L. 2005
• Plasmonic functionality on Si chips Silicon Nanoelectronics and Beyond III, Workshop organized by SRC and NSF, National Science Foundation, Arlington, Virginia Brongersma, Mark, L., Brongersma, Mark, L., Atwater, H., A., Flagan, R., C. 2005
• The future of Plasmonics and Si microphotonics DARPA Frontiers on Quantum Device Engineering Workshop, Los Angeles Brongersma, Mark, L. 2005
• Design of Silicon Based Field-Effect Electro-Optic Modulator With Enhanced Light-Charge Interaction Opt. Lett. Kekatpure, Rohan, D., Schuller, Jon, A., Brongersma, Mark, L. 2005; 30: 2149-2151
• Microring and microdisk optical resonators using silicon nanocrystals and erbium prepared using silicon technology Gardner, D., S., Brongersma, M., L. 2005
• Evidence for stimulated emission in silicon nanocrystal microspheres Chen, H., Sung, I., Y., Tewary, A., Brongersma, M., L., Shin, J., H., Fauchet, P., M. 2005
• Towards CMOS Compatible Plasmonics and Nanophotonics Tutorial at NanoCommerce/SEMI NanoForum, Chicago Brongersma, Mark, L. 2005
• Geometries and materials for subwavelength surface plasmon modes JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Zia, R., Selker, M. D., Catrysse, P. B., Brongersma, M. L. 2004; 21 (12): 2442-2446

  Abstract

  Plasmonic waveguides can guide light along metal-dielectric interfaces with propagating wave vectors of greater magnitude than are available in free space and hence with propagating wavelengths shorter than those in vacuum. This is a necessary, rather than sufficient, condition for subwavelength confinement of the optical mode. By use of the reflection pole method, the two-dimensional modal solutions for single planar waveguides as well as adjacent waveguide systems are solved. We demonstrate that, to achieve subwavelength pitches, a metal-insulator-metal geometry is required with higher confinement factors and smaller spatial extent than conventional insulator-metal-insulator structures. The resulting trade-off between propagation and confinement for surface plasmons is discussed, and optimization by materials selection is described.

  View details for Web of Science ID 000225378200024

  View details for PubMedID 15603083

• Omnidirectional resonance in a metal-dielectric-metal geometry APPLIED PHYSICS LETTERS Shin, H., Yanik, M. F., Fan, S. H., Zia, R., Brongersma, M. L. 2004; 84 (22): 4421-4423

  View details for DOI 10.1063/1.1758306

  View details for Web of Science ID 000221537500021

• New Materials for Microphotonics Brongersma, M., L. 2004
• Towards CMOS Compatible Nanophotonics and Plasmonics Brongersma, M., L. 2004
• Nanoshells: gifts in a gold wrapper NATURE MATERIALS Brongersma, M. L. 2003; 2 (5): 296-297

  View details for Web of Science ID 000182679900012

• Observation of near-field coupling in metal nanoparticle chains using far-field polarization spectroscopy PHYSICAL REVIEW B Maier, S. A., Brongersma, M. L., Kik, P. G., Atwater, H. A. 2002; 65 (19)

  View details for DOI 10.1103/PhysRevB.65.193408

  View details for Web of Science ID 000175860900034

• Electromagnetic energy transport along Yagi arrays EMRS Spring Meeting Maier, S. A., Brongersma, M. L., Atwater, H. A. ELSEVIER SCIENCE BV. 2002: 291–94

  View details for Web of Science ID 000173080700060

• Electromagnetic energy transport along Yagi arrays Mat. Sci. and Eng. Maier, Stefan, A., Pinaud, Blaise, A., Chen, Z., Clemens, Bruce, M., Jaramillo, Thomas, F., Brongersma, Mark, L. 2002; C19: 291–294
• Observation of coupled plasmon-polariton modes of plasmon waveguides for electromagnetic energy transport below the diffraction limit Symposia on Materials and Devices for Optoelectronics and Photonics/Photonic Crystals - From Materials to Devices held at the 2002 MRS Spring Meeting Maier, S. A., Kik, P. G., Brongersma, M. L., Atwater, H. A., Meltzer, S., Requicha, A. A., Koel, B. E. MATERIALS RESEARCH SOCIETY. 2002: 431–436

  View details for Web of Science ID 000178623500059

• Plasmonics - A route to nanoscale optical devices ADVANCED MATERIALS Maier, S. A., Brongersma, M. L., Kik, P. G., Meltzer, S., Requicha, A. A., Atwater, H. A. 2001; 13 (19): 1501-?

  View details for Web of Science ID 000171471300025

• Models for quantitative charge imaging by atomic force microscopy JOURNAL OF APPLIED PHYSICS Boer, E. A., Bell, L. D., Brongersma, M. L., Atwater, H. A. 2001; 90 (6): 2764-2772

  View details for Web of Science ID 000170647500020

• Localized charge injection in SiO2 films containing silicon nanocrystals APPLIED PHYSICS LETTERS Boer, E. A., Brongersma, M. L., Atwater, H. A., Flagan, R. C., Bell, L. D. 2001; 79 (6): 791-793

  View details for Web of Science ID 000170223100030

• Synthesis and characterization of aerosol silicon nanocrystal nonvolatile floating-gate memory devices APPLIED PHYSICS LETTERS Ostraat, M. L., De Blauwe, J. W., Green, M. L., Bell, L. D., Brongersma, M. L., Casperson, J., Flagan, R. C., Atwater, H. A. 2001; 79 (3): 433-435

  View details for Web of Science ID 000169776000052

• Charging of single Si nanocrystals by atomic force microscopy APPLIED PHYSICS LETTERS Boer, E. A., Bell, L. D., Brongersma, M. L., Atwater, H. A., Ostraat, M. L., Flagan, R. C. 2001; 78 (20): 3133-3135

  View details for Web of Science ID 000168559600045

• Colloidal assemblies modified by ion irradiation E-MRS Spring Meeting on Materials Science with Ion Beams Snoeks, E., van Blaaderen, A., van Dillen, T., van Kats, C. M., Velikov, K., Brongersma, M. L., Polman, A. ELSEVIER SCIENCE BV. 2001: 62–68

  View details for Web of Science ID 000169403700009

• Electromagnetic energy transport along arrays of closely spaced metal rods as an analogue to plasmonic devices APPLIED PHYSICS LETTERS Maier, S. A., Brongersma, M. L., Atwater, H. A. 2001; 78 (1): 16-18

  View details for Web of Science ID 000166122000006

• Electromagnetic energy transport below the diffraction limit in periodic metal nanostructures Conference on Controlling and Using Light in Nanometric Domains Maier, S. A., Kik, P. G., Brongersma, M. L., Atwater, H. A. SPIE-INT SOC OPTICAL ENGINEERING. 2001: 22–30

  View details for Web of Science ID 000175017600004

• Manipulation and Charging of Single Si Nanocrystals by Atomic Force Microscopy Appl. Phys. Lett. Boer, E., A., Taubner, T., Brongersma, Mark, L. 2001; 78: 3133
• Electromagnetic energy transfer and switching in nanoparticle chain arrays below the diffraction limit PHYSICAL REVIEW B Brongersma, M. L., Hartman, J. W., Atwater, H. A. 2000; 62 (24): 16356-16359

  View details for Web of Science ID 000166307800037

• Colloidal ellipsoids with continuously variable shape ADVANCED MATERIALS Snoeks, E., van Blaaderen, A., van Dillen, T., van Kats, C. M., Brongersma, M. L., Polman, A. 2000; 12 (20): 1511-1514

  View details for Web of Science ID 000165244300011

• Origin of MeV ion irradiation-induced stress changes in SiO2 JOURNAL OF APPLIED PHYSICS Brongersma, M. L., Snoeks, E., van Dillen, T., Polman, A. 2000; 88 (1): 59-64

  View details for Web of Science ID 000087704000010

• Formation mechanism of silver nanocrystals made by ion irradiation of Na+<-> Ag+ ion-exchanged sodalime silicate glass NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Peters, D. P., Strohhofer, C., Brongersma, M. L., van der Elsken, J., Polman, A. 2000; 168 (2): 237-244

  View details for Web of Science ID 000087241600010

• Strong exciton-erbium coupling in Si nanocrystal-doped SiO2 APPLIED PHYSICS LETTERS Kik, P. G., Brongersma, M. L., Polman, A. 2000; 76 (17): 2325-2327

  View details for Web of Science ID 000086538700001

• Size-dependent electron-hole exchange interaction in Si nanocrystals APPLIED PHYSICS LETTERS Brongersma, M. L., Kik, P. G., Polman, A., Min, K. S., Atwater, H. A. 2000; 76 (3): 351-353

  View details for Web of Science ID 000084675100034

• Monodisperse Silica and ZnS Particles with Continuously Variable Shape Made by Ion Irradiation of Micro-Spheres Advanced Materials Snoeks, E., Cao, L., Arbiol, J., Brongersma, Mark, L., Morral, A. F. 2000; 12: 1511
• Colloidal Assemblies Modified by Ion Irradiation Nucl. Instr. and Meth. Snoeks, E., White, Justin, S., Cai, W., Brongersma, Mark, L. 2000; 178: 62
• Depth distribution of luminescent Si nanocrystals in Si implanted SiO2 films on Si JOURNAL OF APPLIED PHYSICS Brongersma, M. L., Polman, A., Min, K. S., Atwater, H. A. 1999; 86 (2): 759-763

  View details for Web of Science ID 000081171800008

• Activation energy spectra for annealing of ion irradiation induced defects in silica glasses 11th International Conference on Ion Beam Modification of Materials (IBMM98) van Dillen, T., Brongersma, M. L., Snoeks, E., Polman, A. ELSEVIER SCIENCE BV. 1999: 221–26

  View details for Web of Science ID 000078575700039

• Nucl. Intrum. Methods Phys. edited by Vredenberg, A., Polman, A., Stolk, P. 1999
• Activation Energy Spectra for Annealing of Ion Irradiation-induced Defects in Silica Glasses Nucl. Instr. and Meth. van Dillen, T., Kang, J., Park, J., Liu, X., Brongersma, Mark, L. 1999; B 148: 221
• Tuning the emission wavelength of Si nanocrystals in SiO2 by oxidation APPLIED PHYSICS LETTERS Brongersma, M. L., Polman, A., Min, K. S., Boer, E., Tambo, T., Atwater, H. A. 1998; 72 (20): 2577-2579

  View details for Web of Science ID 000073611700027

• Tailoring the Optical Properties of Si Nanocrystals; Materials Issues and Nanocrystal Laser Perspectives Brongersma, M., L., Min, K., S., Boer, E., Tambo, T., Polman, A., Atwater, H., A. 1998
• Low energy k-dependent electronic structure of the layered magnetoresistive oxide La1.2Sr1.8Mn2O7 Symposium on Metallic Magnetic Oxides at the Materials-Research-Society Fall Meeting Saitoh, T., Dessau, D. S., Park, C. H., Shen, Z. X., Villella, P., Hamada, N., Moritomo, Y., Tokura, Y. MATERIALS RESEARCH SOCIETY. 1998: 213–218

  View details for Web of Science ID 000073253400030

• Co-organizer of the Eleventh International Conference on Ion Beam Modification of Materials Brongersma, M., L. 1998
• Temperature dependence of MeV heavy ion irradiation-induced viscous flow in SiO2 APPLIED PHYSICS LETTERS Brongersma, M. L., Snoeks, E., Polman, A. 1997; 71 (12): 1628-1630

  View details for Web of Science ID A1997XW90700012

• Defect-related versus excitonic visible light emission from ion beam synthesized Si nanocrystals in SiO2 APPLIED PHYSICS LETTERS Min, K. S., SHCHEGLOV, K. V., Yang, C. M., Atwater, H. A., Brongersma, M. L., Polman, A. 1996; 69 (14): 2033-2035

  View details for Web of Science ID A1996VJ78300015

• The role of quantum-confined excitons vs defects in the visible luminescence of SiO2 films containing Ge nanocrystals APPLIED PHYSICS LETTERS Min, K. S., SHCHEGLOV, K. V., Yang, C. M., Atwater, H. A., Brongersma, M. L., Polman, A. 1996; 68 (18): 2511-2513

  View details for Web of Science ID A1996UG86600017

• On the Origin of Visible Luminescence from SiO2 Films containing Ge Nanocrystals Min, K., S., Shcheglov, K., V., Yang, C., M., Camata, R., P., Atwater, H., A., Brongersma, M., L. 1996
• Ion beam synthesis of planar opto-electronic devices (reprinted from Nuclear Instruments and Methods in Physics Research, vol 106, pg 393-399, 1995) 9th International Conference on Ion Beam Modification of Materials (IBMM 95) Polman, A., Snoeks, E., VANDENHOVEN, G. N., Brongersma, M. L., Serna, R., Shin, J. H., Kik, P., Radius, E. ELSEVIER SCIENCE BV. 1996: 393–399

  View details for Web of Science ID A1996BG29U00071

• On the origin of visible luminescence from SiO2 films containing Ge nanocrystals Symposium on Surface/Interface and Stress Effects in Electronic Material Nanostructures, at the 1995 MRS Fall Meeting Min, K. S., SHCHEGLOV, K. V., Yang, C. M., Camata, R. P., Atwater, H. A., Brongersma, M. L., Polman, A. MATERIALS RESEARCH SOC. 1996: 247–252

  View details for Web of Science ID A1996BG31L00034

• Ion beam synthesis of planar opto-electronic devices 9th International Conference on Ion Beam Modification of Materials (IBMM 95) Polman, A., Snoeks, E., VANDENHOVEN, G. N., Brongersma, M. L., Serna, R., Shin, J. H., Kik, P., Radius, E. ELSEVIER SCIENCE BV. 1995: 393–99

  View details for Web of Science ID A1995TM52100072

• CORRELATION OF SIZE AND PHOTOLUMINESCENCE FOR GE NANOCRYSTALS IN SIO2 MATRICES Symposium F: Microcrystalline and Nanocrystalline Semiconductors, at the 1994 Fall Meeting of the Materials-Research-Society Yang, C. M., SHCHEGLOV, K. V., Brongersma, M. L., Polman, A., Atwater, H. A. MATERIALS RESEARCH SOCIETY. 1995: 181–186

  View details for Web of Science ID A1995BC88M00028

• Ion Beam Synthesis of Planar Optoelectronic Devices Polman, A., Snoeks, E., van den Hoven, G., N., Brongersma, M., L., Serna, R., Shin, J., H. 1995
• Ion Beam Synthesis of Planar Optoelectronic Devices Nucl. Instrum. and Meth. Polman, A., Hryciw, Aaron, C., Barnard, Edward, S., Brongersma, Mark, L. 1995; B 106: 393
• ION-BEAM SYNTHESIS OF LUMINESCENT SI AND GE NANOCRYSTALS IN A SILICON DIOXIDE MATRIX Symposium on Materials Synthesis and Processing Using Ion Beams, at the 1993 MRS Fall Meeting Atwater, H. A., SHCHEGLOV, K. V., Wong, S. S., Vahala, K. J., Flagan, R. C., Brongersma, M. L., Polman, A. MATERIALS RESEARCH SOC. 1994: 409–420

  View details for Web of Science ID A1994BA28H00062

• ION-BEAM SYNTHESIS OF LUMINESCENT SI AND GE NANOCRYSTALS IN A SILICON DIOXIDE MATRIX Symposium on Crystallization and Related Phenomena in Amorphous Materials, at the 1993 Fall Meeting of the Materials-Research-Society Atwater, H. A., SHCHEGLOV, K. V., Wong, S. S., Vahala, K. J., Flagan, R. C., Brongersma, M. L., Polman, A. MATERIALS RESEARCH SOC. 1994: 363–374

  View details for Web of Science ID A1994BA13A00054

• Ion Beam Synthesis of Luminescent Si and Ge Nanocrystals in a Silicon Dioxide Matrix Atwater, H., A., Shcheglov, K., V., Wong, S., S., Vahala, K., J., Flagan, R., C., Brongersma, M., L. 1994
• CMOS Compatible High-speed Electro-optical Modulator Kekatpure, D., Brongersma, M., L.