Jonathan Fan

All Publications

• Hyperbolic Polaritonic Rulers Based on van der Waals α-MoO3 Waveguides and Resonators. ACS nano Yu, S. J., Yao, H., Hu, G., Jiang, Y., Zheng, X., Fan, S., Heinz, T. F., Fan, J. A. 2023

  Abstract

  Low-dimensional, strongly anisotropic nanomaterials can support hyperbolic phonon polaritons, which feature strong light-matter interactions that can enhance their capabilities in sensing and metrology tasks. In this work, we report hyperbolic polaritonic rulers, based on microscale α-phase molybdenum trioxide (α-MoO3) waveguides and resonators suspended over an ultraflat gold substrate, which exhibit near-field polaritonic characteristics that are exceptionally sensitive to device geometry. Using scanning near-field optical microscopy, we show that these systems support strongly confined image polariton modes that exhibit ideal antisymmetric gap polariton dispersion, which is highly sensitive to air gap dimensions and can be described and predicted using a simple analytic model. Dielectric constants used for modeling are accurately extracted using near-field optical measurements of α-MoO3 waveguides in contact with the gold substrate. We also find that for nanoscale resonators supporting in-plane Fabry-Perot modes, the mode order strongly depends on the air gap dimension in a manner that enables a simple readout of the gap dimension with nanometer precision.

  View details for DOI 10.1021/acsnano.3c08735

  View details for PubMedID 37948673

• Polychromatic metasurfaces for complete control of phase and polarization in the mid-infrared. Light, science & applications Zhou, Y., Fan, J. A. 2023; 12 (1): 249

  Abstract

  Multifunctional metasurfaces based on wavelength-decoupled supercells are experimentally demonstrated, enabling new regimes of optical control for arbitrary orthogonal polarizations at different wavelengths.

  View details for DOI 10.1038/s41377-023-01257-5

  View details for PubMedID 37805594

  View details for PubMedCentralID PMC10560284

• Arbitrary Achromatic Polarization Control with Reconfigurable Metasurface Systems LASER & PHOTONICS REVIEWS Wang, E. W., Yu, S., Phan, T., Dhuey, S., Fan, J. A. 2023

  View details for DOI 10.1002/lpor.202200926

  View details for Web of Science ID 000969340200001

• Snapshot Mueller spectropolarimeter imager. Microsystems & nanoengineering Dai, T., Phan, T., Wang, E. W., Kwon, S., Son, J., Lee, M., Fan, J. A. 2023; 9: 125

  Abstract

  We introduce an imaging system that can simultaneously record complete Mueller polarization responses for a set of wavelength channels in a single image capture. The division-of-focal-plane concept combines a multiplexed illumination scheme based on Fourier optics together with an integrated telescopic light-field imaging system. Polarization-resolved imaging is achieved using broadband nanostructured plasmonic polarizers as functional pinhole apertures. The recording of polarization and wavelength information on the image sensor is highly interpretable. We also develop a calibration approach based on a customized neural network architecture that can produce calibrated measurements in real-time. As a proof-of-concept demonstration, we use our calibrated system to accurately reconstruct a thin film thickness map from a four-inch wafer. We anticipate that our concept will have utility in metrology, machine vision, computational imaging, and optical computing platforms.

  View details for DOI 10.1038/s41378-023-00588-y

  View details for PubMedID 37814609

• Conformal Volumetric Grayscale Metamaterials. Advanced materials (Deerfield Beach, Fla.) Huang, Q., Gan, L. T., Fan, J. A. 2022: e2204688

  Abstract

  Conformal artificial electromagnetic media that feature tailorable responses as a function of incidence wavelength and angle represent universal components for optical engineering. We introduce conformal grayscale metamaterials as a new class of volumetric electromagnetic media capable of supporting highly multiplexed responses and arbitrary, curvilinear form factors. Subwavelength-scale voxels based on irregular shapes are designed to accommodate a continuum of dielectric values, enabling the freeform design process to reliably converge to exceptionally high Figure of Merits for a given multi-objective design problem. Through additive manufacturing of ceramic-polymer composites, we experimentally fabricate microwave metamaterials, designed for the radio frequency range of 8-12GHz, and demonstrate devices with extreme dispersion profiles, an airfoil-shaped beam steering device, and a broadband, broad angle conformal carpet cloak. We anticipate that conformal volumetric metamaterials will lead to new classes of compact and multi-functional imaging, sensing, and communications systems. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/adma.202204688

  View details for PubMedID 36565280

• "Deep approaches to learning" in a project-based nanofabrication graduate course JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY Tang, M., Kommera, S., Raghuram, U., Rincon, M., Xu, X., Fan, J., Howe, R. T. 2022

  View details for DOI 10.1002/jsid.1182

  View details for Web of Science ID 000871256700001

• Reparameterization Approach to Gradient-Based Inverse Design of Three-Dimensional Nanophotonic Devices ACS PHOTONICS Gershnabel, E., Chen, M., Mao, C., Wang, E. W., Lalanne, P., Fan, J. A. 2022

  View details for DOI 10.1021/acsphotonics.2c01160

  View details for Web of Science ID 000874561200001

• Algorithm-Driven Paradigms for Freeform Optical Engineering ACS PHOTONICS Fan, J. A., Chen, M., Jiang, J. 2022; 9 (9): 2860-2871

  View details for DOI 10.1021/acsphotonics.2c00612

  View details for Web of Science ID 000860287300001

• High Speed Simulation and Freeform Optimization of Nanophotonic Devices with Physics-Augmented Deep Learning ACS PHOTONICS Chen, M., Lupoiu, R., Mao, C., Huang, D., Jiang, J., Lalanne, P., Fan, J. A. 2022

  View details for DOI 10.1021/acsphotonics.2c00876

  View details for Web of Science ID 000848111900001

• Electrically Driven Hyperbolic Nanophotonic Resonators as High Speed, Spectrally Selective Thermal Radiators. Nano letters Roberts, J. A., Ho, P., Yu, S., Fan, J. A. 2022

  Abstract

  We introduce and experimentally demonstrate electrically driven, spectrally selective thermal emitters based on globally aligned carbon nanotube metamaterials. The self-assembled metamaterial supports a high degree of nanotube ordering, enabling nanoscale ribbons patterned in the metamaterial to function both as Joule-heated incandescent filaments and as infrared hyperbolic resonators imparting spectral selectivity to the thermal radiation. Devices batch-fabricated on a single chip emit polarized thermal radiation with peak wavelengths dictated by their hyperbolic resonances, and their nanoscale heated dimensions yield modulation rates as high as 1 MHz. As a proof of concept, we show that two sets of thermal emitters on the same chip, operating with different peak wavelengths and modulation rates, can be used to sense carbon dioxide with one detector. We anticipate that the combination of batch fabrication, modulation bandwidth, and spectral tuning with chip-based nanotube thermal emitters will enable new modalities in multiplexed infrared sources.

  View details for DOI 10.1021/acs.nanolett.2c01579

  View details for PubMedID 35849552

• In Situ TEM tensile testing of bicrystals with tailored misorientation angles ACTA MATERIALIA Kiani, M. T., Gan, L. T., Traylor, R., Yang, R., Barr, C. M., Hattar, K., Fan, J. A., Gu, X. 2022; 224

  View details for DOI 10.1016/j.actamat.2021.117505

  View details for Web of Science ID 000793172200002

• Ultrahigh-Quality Infrared Polaritonic Resonators Based on Bottom-Up-Synthesized van der Waals Nanoribbons. ACS nano Yu, S., Jiang, Y., Roberts, J. A., Huber, M. A., Yao, H., Shi, X., Bechtel, H. A., Gilbert Corder, S. N., Heinz, T. F., Zheng, X., Fan, J. A. 1800

  Abstract

  van der Waals nanomaterials supporting phonon polariton quasiparticles possess extraordinary light confinement capabilities, making them ideal systems for molecular sensing, thermal emission, and subwavelength imaging applications, but they require defect-free crystallinity and nanostructured form factors to fully showcase these capabilities. We introduce bottom-up-synthesized alpha-MoO3 structures as nanoscale phonon polaritonic systems that feature tailorable morphologies and crystal qualities consistent with bulk single crystals. alpha-MoO3 nanoribbons serve as low-loss hyperbolic Fabry-Perot nanoresonators, and we experimentally map hyperbolic resonances over four Reststrahlen bands spanning the far- and mid-infrared spectral range, including resonance modes beyond the 10th order. The measured quality factors are the highest from phonon polaritonic van der Waals structures to date. We anticipate that bottom-up-synthesized polaritonic van der Waals nanostructures will serve as an enabling high-performance and low-loss platform for infrared optical and optoelectronic applications.

  View details for DOI 10.1021/acsnano.1c10489

  View details for PubMedID 35041379

• Multifunctional Conformal Grayscale Electromagnetic Metamaterials Huang, Q., Gan, L. T., Fan, J. A., Chang-Hasnain, C. J., Fan, J. A., Zhou, W. SPIE-INT SOC OPTICAL ENGINEERING. 2022

  View details for DOI 10.1117/12.2614563

  View details for Web of Science ID 000836330700001

• Dynamic circular birefringence response with fractured geometric phase metasurface systems. Proceedings of the National Academy of Sciences of the United States of America Wang, E. W., Phan, T., Yu, S. J., Dhuey, S., Fan, J. A. 2022; 119 (12): e2122085119

  Abstract

  SignificanceOptical activity is a fundamental property of symmetry-broken three-dimensional systems and enables control of the polarization state of electromagnetic waves. This work introduces a type of reconfigurable geometric phase response in which shearing displacements between two Pancharatnam-Berry-phase metasurfaces transduce chiral symmetry breaking within nanoscale waveguide structures. These metasurface systems, termed fractured metasurface waveplates, can be tailored to support dynamically tunable, broadband circular birefringence responses. Polarization modulation is based on microscopic motions and uniquely enables high-speed modulation over large area apertures. Our system paves the way for new classes of nanophotonic devices that feature systems-level symmetry breaking for controlling electromagnetic waves, which is relevant for sensing, imaging, and quantum-control applications.

  View details for DOI 10.1073/pnas.2122085119

  View details for PubMedID 35294279

• Ultrahigh-quality van der Waals hyperbolic polariton resonators Yu, S., Jiang, Y., Roberts, J. A., Huber, M. A., Yao, H., Shi, X., Bechtel, H. A., Corder, S. G., Heinz, T. F., Zheng, X., Fan, J. A., Chang-Hasnain, C. J., Fan, J. A., Zhou, W. SPIE-INT SOC OPTICAL ENGINEERING. 2022

  View details for DOI 10.1117/12.2612301

  View details for Web of Science ID 000836330700010

• WaveY-Net: Physics-Augmented Deep Learning for High-Speed Electromagnetic Simulation and Optimization Chen, M., Lupoiu, R., Mao, C., Huang, D., Jiang, J., Lalanne, P., Fan, J. A., Chang-Hasnain, C. J., Fan, J. A., Zhou, W. SPIE-INT SOC OPTICAL ENGINEERING. 2022

  View details for DOI 10.1117/12.2612418

  View details for Web of Science ID 000836330700011

• Optical meta-waveguides for integrated photonics and beyond. Light, science & applications Meng, Y., Chen, Y., Lu, L., Ding, Y., Cusano, A., Fan, J. A., Hu, Q., Wang, K., Xie, Z., Liu, Z., Yang, Y., Liu, Q., Gong, M., Xiao, Q., Sun, S., Zhang, M., Yuan, X., Ni, X. 2021; 10 (1): 235

  Abstract

  The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip. The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits, giving rise to numerous meta-waveguides with unprecedented strength in controlling guided electromagnetic waves. Here, we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms, such as dielectric or plasmonic waveguides and optical fibers. Foundational results and representative applications are comprehensively summarized. Brief physical models with explicit design tutorials, either physical intuition-based design methods or computer algorithms-based inverse designs, are cataloged as well. We highlight how meta-optics can infuse new degrees of freedom to waveguide-based devices and systems, by enhancing light-matter interaction strength to drastically boost device performance, or offering a versatile designer media for manipulating light in nanoscale to enable novel functionalities. We further discuss current challenges and outline emerging opportunities of this vibrant field for various applications in photonic integrated circuits, biomedical sensing, artificial intelligence and beyond.

  View details for DOI 10.1038/s41377-021-00655-x

  View details for PubMedID 34811345

• Detection of Trace Impurity Gradients in Noble Metals by the Photothermoelectric Effect JOURNAL OF PHYSICAL CHEMISTRY C Evans, C., Gan, L. T., Yang, R., Abbasi, M., Wang, X., Traylor, R., Fan, J. A., Natelson, D. 2021; 125 (31): 17509-17517

  View details for DOI 10.1021/acs.jpcc.1c04927

  View details for Web of Science ID 000685650400064

• Raman spectroscopic study of artificially twisted and non-twisted trilayer graphene APPLIED PHYSICS LETTERS Kim, S., Lee, D., Wang, B., Yu, S., Watanabe, K., Taniguchi, T., Fan, J. A., Xue, J., Lee, K. 2021; 118 (13)

  View details for DOI 10.1063/5.0040716

  View details for Web of Science ID 000636343000001

• Codoping Mg-Mn Based Oxygen Carrier with Lithium and Tungsten for Enhanced C-2 Yield in a Chemical Looping Oxidative Coupling of Methane System ACS SUSTAINABLE CHEMISTRY & ENGINEERING Baser, D. S., Cheng, Z., Fan, J. A., Fan, L. 2021; 9 (7): 2651–60

  View details for DOI 10.1021/acssuschemeng.0c07241

  View details for Web of Science ID 000621667100004

• Multiobjective and categorical global optimization of photonic structures based on ResNet generative neural networks NANOPHOTONICS Jiang, J., Fan, J. A. 2021; 10 (1): 361–69

  View details for DOI 10.1515/nanoph-2020-0407

  View details for Web of Science ID 000597359300028

• Deep neural networks for the evaluation and design of photonic devices NATURE REVIEWS MATERIALS Jiang, J., Chen, M., Fan, J. A. 2020

  View details for DOI 10.1038/s41578-020-00260-1

  View details for Web of Science ID 000599797100001

• Mechanistic Insight into Hydrogen-Assisted Carbon Dioxide Reduction with Ilmenite ENERGY & FUELS Cheng, Z., Baser, D. S., Shah, V., Fan, J. A., Fan, L. 2020; 34 (12): 15370–78

  View details for DOI 10.1021/acs.energyfuels.0c03214

  View details for Web of Science ID 000600407600020

• Design Space Reparameterization Enforces Hard Geometric Constraints in Inverse-Designed Nanophotonic Devices ACS PHOTONICS Chen, M., Jiang, J., Fan, J. A. 2020; 7 (11): 3141–51

  View details for DOI 10.1021/acsphotonics.0c01202

  View details for Web of Science ID 000592916800023

• SBA-16-Mediated Nanoparticles Enabling Accelerated Kinetics in Cyclic Methane Conversion to Syngas at Low Temperatures ACS APPLIED ENERGY MATERIALS Liu, Y., Qin, L., Pan, J., Chen, Y., Goetze, J. W., Xu, D., Fan, J. A., Fan, L. 2020; 3 (10): 9833–40

  View details for DOI 10.1021/acsaem.0c01495

  View details for Web of Science ID 000586710300042

• Multiple Tunable Hyperbolic Resonances in Broadband Infrared Carbon-Nanotube Metamaterials PHYSICAL REVIEW APPLIED Roberts, J., Ho, P., Yu, S., Wu, X., Luo, Y., Wilson, W. L., Falk, A. L., Fan, J. A. 2020; 14 (4)

  View details for DOI 10.1103/PhysRevApplied.14.044006

  View details for Web of Science ID 000576948600002

• Thermoelectric response from grain boundaries and lattice distortions in crystalline gold devices. Proceedings of the National Academy of Sciences of the United States of America Evans, C. I., Yang, R., Gan, L. T., Abbasi, M., Wang, X., Traylor, R., Fan, J. A., Natelson, D. 2020

  Abstract

  The electronic Seebeck response in a conductor involves the energy-dependent mean free path of the charge carriers and is affected by crystal structure, scattering from boundaries and defects, and strain. Previous photothermoelectric (PTE) studies have suggested that the thermoelectric properties of polycrystalline metal nanowires are related to grain structure, although direct evidence linking crystal microstructure to the PTE response is difficult to elucidate. Here, we show that room temperature scanning PTE measurements are sensitive probes that can detect subtle changes in the local Seebeck coefficient of gold tied to the underlying defects and strain that mediate crystal deformation. This connection is revealed through a combination of scanning PTE and electron microscopy measurements of single-crystal and bicrystal gold microscale devices. Unexpectedly, the photovoltage maps strongly correlate with gradually varying crystallographic misorientations detected by electron backscatter diffraction. The effects of individual grain boundaries and differing grain orientations on the PTE signal are minimal. This scanning PTE technique shows promise for identifying minor structural distortions in nanoscale materials and devices.

  View details for DOI 10.1073/pnas.2002284117

  View details for PubMedID 32900922

• Robust Freeform Metasurface Design Based on Progressively Growing Generative Networks ACS PHOTONICS Wen, F., Jiang, J., Fan, J. A. 2020; 7 (8): 2098–2104

  View details for DOI 10.1021/acsphotonics.0c00539

  View details for Web of Science ID 000563072500026

• Numerical Optimization Methods for Metasurfaces LASER & PHOTONICS REVIEWS Elsawy, M. R., Lanteri, S., Duvigneau, R., Fan, J. A., Genevet, P. 2020

  View details for DOI 10.1002/lpor.201900445

  View details for Web of Science ID 000559297600001

• Cobalt doping modi fication for enhanced methane conversion at low temperature in chemical looping reforming systems CATALYSIS TODAY Guo, M., Cheng, Z., Liu, Y., Qin, L., Goetze, J., Fan, J. A., Fan, L. 2020; 350: 156–64

  View details for DOI 10.1016/j.cattod.2019.06.016

  View details for Web of Science ID 000541709100007

• MetaNet: a new paradigm for data sharing in photonics research OPTICS EXPRESS Jiang, J., Lupoiu, R., Wang, E. W., Sell, D., Hugonin, J., Lalanne, P., Fan, J. A. 2020; 28 (9): 13670–81

  Abstract

  Optimization methods are playing an increasingly important role in all facets of photonics engineering, from integrated photonics to free space diffractive optics. However, efforts in the photonics community to develop optimization algorithms remain uncoordinated, which has hindered proper benchmarking of design approaches and access to device designs based on optimization. We introduce MetaNet, an online database of photonic devices and design codes intended to promote coordination and collaboration within the photonics community. Using metagratings as a model system, we have uploaded over one hundred thousand device layouts to the database, as well as source code for implementations of local and global topology optimization methods. Further analyses of these large datasets allow the distribution of optimized devices to be visualized for a given optimization method. We expect that the coordinated research efforts enabled by MetaNet will expedite algorithm development for photonics design.

  View details for DOI 10.1364/OE.388378

  View details for Web of Science ID 000530854700092

  View details for PubMedID 32403837

• 3D Electromagnetic Reconfiguration Enabled by Soft Continuum Robots IEEE ROBOTICS AND AUTOMATION LETTERS Gan, L. T., Blumenschein, L. H., Huang, Z., Okamura, A. M., Hawkes, E. W., Fan, J. A. 2020; 5 (2): 1704–11

  View details for DOI 10.1109/LRA.2020.2969922

  View details for Web of Science ID 000526520500005

• Freeform metasurface design based on topology optimization MRS BULLETIN Fan, J. A. 2020; 45 (3): 196–201

  View details for DOI 10.1557/mrs.2020.62

  View details for Web of Science ID 000524941800013

• Broadband Mid-Infrared Resonances in Aligned Carbon Nanotube Films Roberts, J., Ho, P., Yu, S., Schoeche, S., Luo, Y., Wilson, W. L., Falk, A. L., Fan, J. A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001385

• Reparameterization to Enforce Constraints in the Inverse Design of Metasurfaces Chen, M., Jiang, J., Fan, J. A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090000187

• Highly confined plasmons in individual single-walled carbon nanotube nanoantennas Yu, S., Roberts, J., Lin, Q., Bohaichuk, S., Luo, Y., Choi, Y., Ho, P., Lee, K., Falk, A. L., Wilson, W. L., Pop, E., Wong, H., Fan, J. A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090002178

• Mid-IR and UV-Vis-NIR Mueller matrix ellipsometry characterization of tunable hyperbolic metamaterials based on self-assembled carbon nanotubes Journal of Vacuum Science & Technology B Schoche, S., Ho, P., Roberts, J. A., Yu, S. J., Fan, J. A., Falk, A. L. 2020; 38

  View details for DOI 10.1116/1.5130888

• 1 kW, Multi-MHz Wireless Charging for Electric Transportation Phan, T., Zulauf, G., Fan, J. A., Rivas-Davila, J. M., IEEE IEEE. 2020: 795-801

  View details for Web of Science ID 000659968200117

• Free-Form Diffractive Metagrating Design Based on Generative Adversarial Networks. ACS nano Jiang, J., Sell, D., Hoyer, S., Hickey, J., Yang, J., Fan, J. A. 2019

  Abstract

  A key challenge in metasurface design is the development of algorithms that can effectively and efficiently produce high-performance devices. Design methods based on iterative optimization can push the performance limits of metasurfaces, but they require extensive computational resources that limit their implementation to small numbers of microscale devices. We show that generative neural networks can train from images of periodic, topology-optimized metagratings to produce high-efficiency, topologically complex devices operating over a broad range of deflection angles and wavelengths. Further iterative optimization of these designs yields devices with enhanced robustness and efficiencies, and these devices can be utilized as additional training data for network refinement. In this manner, generative networks can be trained, with a one-time computation cost, and used as a design tool to facilitate the production of near-optimal, topologically complex device designs. We envision that such data-driven design methodologies can apply to other physical sciences domains that require the design of functional elements operating across a wide parameter space.

  View details for DOI 10.1021/acsnano.9b02371

  View details for PubMedID 31314492

• Global Optimization of Dielectric Metasurfaces Using a Physics-Driven Neural Network. Nano letters Jiang, J., Fan, J. A. 2019

  Abstract

  We present a global optimizer, based on a conditional generative neural network, which can output ensembles of highly efficient topology-optimized metasurfaces operating across a range of parameters. A key feature of the network is that it initially generates a distribution of devices that broadly samples the design space and then shifts and refines this distribution toward favorable design space regions over the course of optimization. Training is performed by calculating the forward and adjoint electromagnetic simulations of outputted devices and using the subsequent efficiency gradients for backpropagation. With metagratings operating across a range of wavelengths and angles as a model system, we show that devices produced from the trained generative network have efficiencies comparable to or better than the best devices produced by adjoint-based topology optimization, while requiring less computational cost. Our reframing of adjoint-based optimization to the training of a generative neural network applies generally to physical systems that can utilize gradients to improve performance.

  View details for DOI 10.1021/acs.nanolett.9b01857

  View details for PubMedID 31294997

• Tunable Hyperbolic Metamaterials Based on Self-Assembled Carbon Nanotubes NANO LETTERS Roberts, J., Yu, S., Ho, P., Schoeche, S., Falk, A. L., Fan, J. A. 2019; 19 (5): 3131–37

  View details for DOI 10.1021/acs.nanolett.9b00552

  View details for Web of Science ID 000467781900046

• Coupling between subwavelength nano-slit lattice modes and metal-insulator-graphene cavity modes: a semi-analytical model OSA CONTINUUM Edee, K., Benrhouma, M., Antezza, M., Fan, J., Guizal, B. 2019; 2 (4): 1296–1309

  View details for DOI 10.1364/OSAC.2.001296

  View details for Web of Science ID 000464918500025

• Review of numerical optimization techniques for meta-device design [Invited] OPTICAL MATERIALS EXPRESS Campbell, S. D., Sell, D., Jenkins, R. P., Whiting, E. B., Fan, J. A., Werner, D. H. 2019; 9 (4): 1842–63

  View details for DOI 10.1364/OME.9.001842

  View details for Web of Science ID 000462885100027

• Ternary content-addressable memory with MoS2 transistors for massively parallel data search NATURE ELECTRONICS Yang, R., Li, H., Smithe, K. H., Kim, T. R., Okabe, K., Pop, E., Fan, J. A., Wong, H. 2019; 2 (3): 108–14

  View details for DOI 10.1038/s41928-019-0220-7

  View details for Web of Science ID 000463819800010

• Large-area MRI-compatible epidermal electronic interfaces for prosthetic control and cognitive monitoring NATURE BIOMEDICAL ENGINEERING Tian, L., Zimmerman, B., Akhtar, A., Yu, K., Moore, M., Wu, J., Larsen, R. J., Lee, J., Li, J., Liu, Y., Metzger, B., Qu, S., Guo, X., Mathewson, K. E., Fan, J. A., Cornman, J., Fatina, M., Xie, Z., Mao, Y., Zhang, J., Zhang, Y., Dolcos, F., Fabiani, M., Gratton, G., Bretl, T., Hargrove, L. J., Braun, P., Huang, Y., Rogers, J. A. 2019; 3 (3): 194-+

  View details for DOI 10.1038/s41551-019-0347-x

  View details for Web of Science ID 000460576800010

• Robust design of topology-optimized metasurfaces OPTICAL MATERIALS EXPRESS Wang, E. W., Sell, D., Phan, T., Fan, J. A. 2019; 9 (2): 469–82

  View details for DOI 10.1364/OME.9.000469

  View details for Web of Science ID 000457500500013

• High-Throughput Growth of Microscale Gold Bicrystals for Single-Grain-Boundary Studies. Advanced materials (Deerfield Beach, Fla.) Gan, L. T., Yang, R. n., Traylor, R. n., Cai, W. n., Nix, W. D., Fan, J. A. 2019: e1902189

  Abstract

  The study of grain boundaries is the foundation to understanding many of the intrinsic physical properties of bulk metals. Here, the preparation of microscale thin-film gold bicrystals, using rapid melt growth, is presented as a model system for studies of single grain boundaries. This material platform utilizes standard fabrication tools and supports the high-yield growth of thousands of bicrystals per wafer, each containing a grain boundary with a unique <111> tilt character. The crystal growth dynamics of the gold grains in each bicrystal are mediated by platinum gradients, which originate from the gold-platinum seeds responsible for gold crystal nucleation. This crystallization mechanism leads to a decoupling between crystal nucleation and crystal growth, and it ensures that the grain boundaries form at the middle of the gold microstructures and possess a uniform distribution of misorientation angles. It is envisioned that these bicrystals will enable the systematic study of the electrical, optical, chemical, thermal, and mechanical properties of individual grain boundary types.

  View details for DOI 10.1002/adma.201902189

  View details for PubMedID 31197897

• Tunable Hyperbolic Plasmons in Self-Assembled Carbon Nanotube Metamaterials Roberts, J., Yu, S., Falk, A. L., Ho, P., Schoeche, S., Fan, J. A., IEEE IEEE. 2019

  View details for Web of Science ID 000482226300251

• Generating high performance, topologically-complex metasurfaces with neural networks Fan, J. A., IEEE IEEE. 2019

  View details for Web of Science ID 000482226300137

• Simulator-based training of generative neural networks for the inverse design of metasurfaces Nanophotonics Jiang, J., Fan, J. A. 2019

  View details for DOI 10.1515/nanoph-2019-0330

• High-efficiency, large-area, topology-optimized metasurfaces. Light, science & applications Phan, T. n., Sell, D. n., Wang, E. W., Doshay, S. n., Edee, K. n., Yang, J. n., Fan, J. A. 2019; 8: 48

  Abstract

  Metasurfaces are ultrathin optical elements that are highly promising for constructing lightweight and compact optical systems. For their practical implementation, it is imperative to maximize the metasurface efficiency. Topology optimization provides a pathway for pushing the limits of metasurface efficiency; however, topology optimization methods have been limited to the design of microscale devices due to the extensive computational resources that are required. We introduce a new strategy for optimizing large-area metasurfaces in a computationally efficient manner. By stitching together individually optimized sections of the metasurface, we can reduce the computational complexity of the optimization from high-polynomial to linear. As a proof of concept, we design and experimentally demonstrate large-area, high-numerical-aperture silicon metasurface lenses with focusing efficiencies exceeding 90%. These concepts can be generalized to the design of multifunctional, broadband diffractive optical devices and will enable the implementation of large-area, high-performance metasurfaces in practical optical systems.

  View details for DOI 10.1038/s41377-019-0159-5

  View details for PubMedID 31149333

  View details for PubMedCentralID PMC6538635

• Near 100% CO selectivity in nanoscaled iron-based oxygen carriers for chemical looping methane partial oxidation. Nature communications Liu, Y. n., Qin, L. n., Cheng, Z. n., Goetze, J. W., Kong, F. n., Fan, J. A., Fan, L. S. 2019; 10 (1): 5503

  Abstract

  Chemical looping methane partial oxidation provides an energy and cost effective route for methane utilization. However, there is considerable CO2 co-production in current chemical looping systems, rendering a decreased productivity in value-added fuels or chemicals. In this work, we demonstrate that the co-production of CO2 can be dramatically suppressed in methane partial oxidation reactions using iron oxide nanoparticles embedded in mesoporous silica matrix. We experimentally obtain near 100% CO selectivity in a cyclic redox system at 750-935 °C, which is a significantly lower temperature range than in conventional oxygen carrier systems. Density functional theory calculations elucidate the origins for such selectivity and show that low-coordinated lattice oxygen atoms on the surface of nanoparticles significantly promote Fe-O bond cleavage and CO formation. We envision that embedded nanostructured oxygen carriers have the potential to serve as a general materials platform for redox reactions with nanomaterials at high temperatures.

  View details for DOI 10.1038/s41467-019-13560-0

  View details for PubMedID 31796744

• Metal oxide redox chemistry for chemical looping processes NATURE REVIEWS CHEMISTRY Zeng, L., Cheng, Z., Fan, J. A., Fan, L., Gong, J. 2018; 2 (11): 349–64

  View details for DOI 10.1038/s41570-018-0046-2

  View details for Web of Science ID 000449787400005

• Understanding Interlayer Coupling in TMD-hBN Heterostructure by Raman Spectroscopy IEEE TRANSACTIONS ON ELECTRON DEVICES Ding, L., Ukhtary, M., Chubarov, M., Choudhury, T. H., Zhang, F., Yang, R., Zhang, A., Fan, J. A., Terrones, M., Redwing, J. M., Yang, T., Li, M., Saito, R., Huang, S. 2018; 65 (10): 4059–67

  View details for DOI 10.1109/TED.2018.2847230

  View details for Web of Science ID 000445239700004

• Ultra-High-Efficiency Anomalous Refraction with Dielectric Metasurfaces ACS PHOTONICS Sell, D., Yang, J., Wang, E. W., Phan, T., Doshay, S., Fan, J. A. 2018; 5 (6): 2402–7

  View details for DOI 10.1021/acsphotonics.8b00183

  View details for Web of Science ID 000436211900041

• A Tip-Extending Soft Robot Enables Reconfigurable and Deployable Antennas IEEE ROBOTICS AND AUTOMATION LETTERS Blumenschein, L. H., Gan, L. T., Fan, J. A., Okamura, A. M., Hawkes, E. W. 2018; 3 (2): 949–56

  View details for DOI 10.1109/LRA.2018.2793303

  View details for Web of Science ID 000424646100014

• Single-crystal metal growth on amorphous insulating substrates PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Zhang, K., Pitner, X., Yang, R., Nix, W. D., Plummer, J. D., Fan, J. A. 2018; 115 (4): 685–89

  Abstract

  Metal structures on insulators are essential components in advanced electronic and nanooptical systems. Their electronic and optical properties are closely tied to their crystal quality, due to the strong dependence of carrier transport and band structure on defects and grain boundaries. Here we report a method for creating patterned single-crystal metal microstructures on amorphous insulating substrates, using liquid phase epitaxy. In this process, the patterned metal microstructures are encapsulated in an insulating crucible, together with a small seed of a differing material. The system is heated to temperatures above the metal melting point, followed by cooling and metal crystallization. During the heating process, the metal and seed form a high-melting-point solid solution, which directs liquid epitaxial metal growth. High yield of single-crystal metal with different sizes is confirmed with electron backscatter diffraction images, after removing the insulating crucible. Unexpectedly, the metal microstructures crystallize with the [Formula: see text] direction normal to the plane of the film. This platform technology will enable the large-scale integration of high-performance plasmonic and electronic nanosystems.

  View details for PubMedID 29311332

• High-performance axicon lenses based on high-contrast, multilayer gratings APL PHOTONICS Doshay, S., Sell, D., Yang, J., Yang, R., Fan, J. A. 2018; 3 (1)

  View details for DOI 10.1063/1.5009760

  View details for Web of Science ID 000423871300003

• Evaluating the Microwave Performance of Epidermal Electronics with Equivalent Transmission Line Modeling Chang, T., Fan, J. A., Lee, T. H., IEEE IEEE. 2018: 40–42

  View details for Web of Science ID 000502126700092

• Freeform Metagratings Based on Complex Light Scattering Dynamics for Extreme, High Efficiency Beam Steering ANNALEN DER PHYSIK Yang, J., Sell, D., Fan, J. A. 2018; 530 (1)

  View details for DOI 10.1002/andp.201700302

  View details for Web of Science ID 000423177000010

• A General Strategy for Stretchable Microwave Antenna Systems using Serpentine Mesh Layouts ADVANCED FUNCTIONAL MATERIALS Chang, T., Tanabe, Y., Wojcik, C. C., Barksdale, A. C., Doshay, S., Dong, Z., Liu, H., Zhang, M., Chen, Y., Su, Y., Lee, T. H., Ho, J. S., Fan, J. A. 2017; 27 (46)

  View details for DOI 10.1002/adfm.201703059

  View details for Web of Science ID 000417187200005

• Periodic Dielectric Metasurfaces with High-Efficiency, Multiwavelength Functionalities ADVANCED OPTICAL MATERIALS Sell, D., Yang, J., Doshay, S., Fan, J. A. 2017; 5 (23)

  View details for DOI 10.1002/adom.201700645

  View details for Web of Science ID 000416832000010

• Strain-Limiting Substrates Based on Nonbuckling, Prestrain-Free Mechanics for Robust Stretchable Electronics JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Zhang, M., Liu, H., Cao, P., Chen, B., Hu, J., Chen, Y., Pan, B., Fan, J. A., Li, R., Zhang, L., Su, Y. 2017; 84 (12)

  View details for DOI 10.1115/1.4038173

  View details for Web of Science ID 000414627900010

• Improved cyclic redox reactivity of lanthanum modified iron-based oxygen carriers in carbon monoxide chemical looping combustion JOURNAL OF MATERIALS CHEMISTRY A Qin, L., Guo, M., Cheng, Z., Xu, M., Liu, Y., Xu, D., Fan, J. A., Fan, L. 2017; 5 (38): 20153–60

  View details for DOI 10.1039/c7ta04228k

  View details for Web of Science ID 000412781700008

• Analysis of material selection on dielectric metasurface performance OPTICS EXPRESS Yang, J., Fan, J. A. 2017; 25 (20): 23899–909

  Abstract

  Dielectric metasurfaces are ultra-thin devices that can shape optical wavefronts with extreme control. While an assortment of materials possessing a wide range of dielectric constants have been proposed and implemented, the minimum dielectric contrast required for metasurfaces to achieve high-efficiency performance, for a given device function and feature size constraint, is unclear. In this Article, we examine the impact of dielectric material selection on metasurface efficiency at optical frequencies. As a model system, we design transmissive, single-layer periodic metasurfaces (i.e., metagratings) using topology optimization, and we sweep device thickness and light deflection angle for differing material types. We find that for modest deflection angles below 40 degrees, materials with relatively low dielectric constants near 4 can be used to produce metagratings with efficiencies over 80%. However, ultra-high-efficiency devices designed for large deflection angles and multiple functions require materials with high dielectric constants comparable to silicon. We also identify, for all materials, a minimum device thickness required for optimal metagrating performance that scales inversely with dielectric constant. Our work presents materials selection guidelines for high-performance metasurfaces operating at visible and infrared wavelengths.

  View details for DOI 10.1364/OE.25.023899

  View details for Web of Science ID 000412048500045

  View details for PubMedID 29041339

• Topology-optimized metasurfaces: impact of initial geometric layout OPTICS LETTERS Yang, J., Fan, J. A. 2017; 42 (16): 3161–64

  Abstract

  Topology optimization is a powerful iterative inverse design technique in metasurface engineering and can transform an initial layout into a high-performance device. With this method, devices are optimized within a local design phase space, making the identification of suitable initial geometries essential. In this Letter, we examine the impact of initial geometric layout on the performance of large-angle (75 deg) topology-optimized metagrating deflectors. We find that when conventional metasurface designs based on dielectric nanoposts are used as initial layouts for topology optimization, the final devices have efficiencies around 65%. In contrast, when random initial layouts are used, the final devices have ultra-high efficiencies that can reach 94%. Our numerical experiments suggest that device topologies based on conventional metasurface designs may not be suitable to produce ultra-high-efficiency, large-angle metasurfaces. Rather, initial geometric layouts with non-trivial topologies and shapes are required.

  View details for DOI 10.1364/OL.42.003161

  View details for Web of Science ID 000407640000027

  View details for PubMedID 28809897

• Large-Angle, Multifunctional Metagratings Based on Freeform Multimode Geometries. Nano letters Sell, D., Yang, J., Doshay, S., Yang, R., Fan, J. A. 2017

  Abstract

  We show that silicon-based metagratings capable of large-angle, multifunctional performance can be realized using inverse freeform design. These devices consist of nonintuitive nanoscale patterns and support a large number of spatially overlapping optical modes per unit area. The quantity of modes, in combination with their optimized responses, provides the degrees of freedom required to produce high-efficiency devices. To demonstrate the power and versatility of our approach, we fabricate metagratings that can efficiently deflect light to 75° angles and multifunctional devices that can steer beams to different diffraction orders based on wavelength. A theoretical analysis of the Bloch modes supported by these devices elucidates the spatial mode profiles and coupling dynamics that make high-performance beam deflection possible. This approach represents a new paradigm in nano-optical mode engineering and utilizes different physics from the current state-of-the-art, which is based on the stitching of noninteracting waveguide structures. We envision that inverse design will enable new classes of high-performance photonic systems and new strategies toward the nanoscale control of light fields.

  View details for DOI 10.1021/acs.nanolett.7b01082

  View details for PubMedID 28459583

• In-Plane Deformation Mechanics for Highly Stretchable Electronics. Advanced materials Su, Y., Ping, X., Yu, K. J., Lee, J. W., Fan, J. A., Wang, B., Li, M., Li, R., Harburg, D. V., Huang, Y., Yu, C., Mao, S., Shim, J., Yang, Q., Lee, P., Armonas, A., Choi, K., Yang, Y., Paik, U., Chang, T., Dawidczyk, T. J., Huang, Y., Wang, S., Rogers, J. A. 2017; 29 (8)

  Abstract

  Scissoring in thick bars suppresses buckling behavior in serpentine traces that have thicknesses greater than their widths, as detailed in a systematic set of analytical and experimental studies. Scissoring in thick copper traces enables elastic stretchability as large as ≈350%, corresponding to a sixfold improvement over previously reported values for thin geometries (≈60%).

  View details for DOI 10.1002/adma.201604989

  View details for PubMedID 28004863

• Impact of 1% Lanthanum Dopant on Carbonaceous Fuel Redox Reactions with an Iron-Based Oxygen Carrier in Chemical Looping Processes ACS ENERGY LETTERS Qin, L., Cheng, Z., Guo, M., Xu, M., Fan, J. A., Fan, L. 2017; 2 (1): 70-74

  View details for DOI 10.1021/acsenergylett.6b0051

  View details for Web of Science ID 000392260400011

• 2D Molybdenum Disulfide (MoS2) Transistors Driving RRAMs with 1T1R Configuration Yang, R., Li, H., Smithe, K. H., Kim, T. R., Okabe, K., Pop, E., Fan, J. A., Wong, H., IEEE IEEE. 2017

  View details for Web of Science ID 000424868900117

• Characterization of Stretchable Serpentine Microwave Devices for Wearable Electronics Chang, T., Wojcik, C., Su, Y., Rogers, J. A., Lee, T. H., Fan, J. A., IEEE IEEE. 2017: 207–10

  View details for Web of Science ID 000425241500055

• Visible Light Metasurfaces Based on Single-Crystal Silicon ACS PHOTONICS Sell, D., Yang, J., Doshay, S., Zhang, K., Fan, J. A. 2016; 3 (10): 1919-1925

  View details for DOI 10.1021/acsphotonics.6b00436

  View details for Web of Science ID 000385992200026

• Electrochemically Programmable Plasmonic Antennas. ACS nano Dong, S., Zhang, K., Yu, Z., Fan, J. A. 2016; 10 (7): 6716-6724

  Abstract

  Plasmonic antennas are building blocks in advanced nano-optical systems due to their ability to tailor optical response based on their geometry. We propose an electrochemical approach to program the optical properties of dipole antennas in a scalable, fast, and energy-efficient manner. These antennas comprise two arms, one serving as an anode and the other a cathode, separated by a solid electrolyte. As a voltage is applied between the antenna arms, a conductive filament either grows or dissolves within the electrolyte, modifying the antenna load. We probe the dynamics of stochastic filament formation and their effects on plasmonic mode programming using a combination of three-dimensional optical and electronic simulations. In particular, we identify device operation regimes in which the charge-transfer plasmon mode can be programmed to be "on" or "off." We also identify, unexpectedly, a strong correlation between DC filament resistance and charge-transfer plasmon mode frequency that is insensitive to the detailed filament morphology. We envision that the scalability of our electrochemical platform can generalize to large-area reconfigurable metamaterials and metasurfaces for on-chip and free-space applications.

  View details for DOI 10.1021/acsnano.6b02031

  View details for PubMedID 27328022

• Epidermal radio frequency electronics for wireless power transfer. Microsystems & nanoengineering Huang, X. n., Liu, Y. n., Kong, G. W., Seo, J. H., Ma, Y. n., Jang, K. I., Fan, J. A., Mao, S. n., Chen, Q. n., Li, D. n., Liu, H. n., Wang, C. n., Patnaik, D. n., Tian, L. n., Salvatore, G. A., Feng, X. n., Ma, Z. n., Huang, Y. n., Rogers, J. A. 2016; 2: 16052

  Abstract

  Epidermal electronic systems feature physical properties that approximate those of the skin, to enable intimate, long-lived skin interfaces for physiological measurements, human-machine interfaces and other applications that cannot be addressed by wearable hardware that is commercially available today. A primary challenge is power supply; the physical bulk, large mass and high mechanical modulus associated with conventional battery technologies can hinder efforts to achieve epidermal characteristics, and near-field power transfer schemes offer only a limited operating distance. Here we introduce an epidermal, far-field radio frequency (RF) power harvester built using a modularized collection of ultrathin antennas, rectifiers and voltage doublers. These components, separately fabricated and tested, can be integrated together via methods involving soft contact lamination. Systematic studies of the individual components and the overall performance in various dielectric environments highlight the key operational features of these systems and strategies for their optimization. The results suggest robust capabilities for battery-free RF power, with relevance to many emerging epidermal technologies.

  View details for PubMedID 31057838

  View details for PubMedCentralID PMC6444737

• Optics and Nonlinear Buckling Mechanics in Large-Area, Highly Stretchable Arrays of Plasmonic Nano structures ACS NANO Gao, L., Zhang, Y., Zhang, H., Doshay, S., Xie, X., Luo, H., Shah, D., Shi, Y., Xu, S., Fang, H., Fan, J. A., Nordlander, P., Huang, Y., Rogers, J. A. 2015; 9 (6): 5968-5975

  Abstract

  Large-scale, dense arrays of plasmonic nanodisks on low-modulus, high-elongation elastomeric substrates represent a class of tunable optical systems, with reversible ability to shift key optical resonances over a range of nearly 600 nm at near-infrared wavelengths. At the most extreme levels of mechanical deformation (strains >100%), nonlinear buckling processes transform initially planar arrays into three-dimensional configurations, in which the nanodisks rotate out of the plane to form linear arrays with "wavy" geometries. Analytical, finite-element, and finite-difference time-domain models capture not only the physics of these buckling processes, including all of the observed modes, but also the quantitative effects of these deformations on the plasmonic responses. The results have relevance to mechanically tunable optical systems, particularly to soft optical sensors that integrate on or in the human body.

  View details for DOI 10.1021/acsnano.5b00716

  View details for Web of Science ID 000356988500037

  View details for PubMedID 25906085

• Materials and Fractal Designs for 3D Multifunctional Integumentary Membranes with Capabilities in Cardiac Electrotherapy ADVANCED MATERIALS Xu, L., Gutbrod, S. R., Ma, Y., Petrossians, A., Liu, Y., Webb, R. C., Fan, J. A., Yang, Z., Xu, R., Whalen, J. J., Weiland, J. D., Huang, Y., Efimov, I. R., Rogers, J. A. 2015; 27 (10): 1731-?

  Abstract

  Advanced materials and fractal design concepts form the basis of a 3D conformal electronic platform with unique capabilities in cardiac electrotherapies. Fractal geometries, advanced electrode materials, and thin, elastomeric membranes yield a class of device capable of integration with the entire 3D surface of the heart, with unique operational capabilities in low power defibrillation. Co-integrated collections of sensors allow simultaneous monitoring of physiological responses. Animal experiments on Langendorff-perfused rabbit hearts demonstrate the key features of these systems.

  View details for DOI 10.1002/adma.201405017

  View details for Web of Science ID 000350754100013

  View details for PubMedID 25641076

  View details for PubMedCentralID PMC4527319

• Elasticity of Fractal Inspired Interconnects SMALL Su, Y., Wang, S., Huang, Y., Luan, H., Dong, W., Fan, J. A., Yang, Q., Rogers, J. A., Huang, Y. 2015; 11 (3): 367-373

  Abstract

  The use of fractal-inspired geometric designs in electrical interconnects represents an important approach to simultaneously achieve large stretchability and high aerial coverage of active devices for stretchable electronics. The elastic stiffness of fractal interconnects is determined analytically in this paper. Specifically, the elastic energy and the tensile stiffness for an order n fractal interconnect of arbitrary shape are obtained, and are verified by the finite element analysis and experiments.

  View details for DOI 10.1002/smll.201401181

  View details for Web of Science ID 000348139800013

  View details for PubMedID 25183293

• A hierarchical computational model for stretchable interconnects with fractal-inspired designs JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Zhang, Y., Fu, H., Xu, S., Fan, J. A., Hwang, K., Jiang, J., Rogers, J. A., Huang, Y. 2014; 72: 115–30

  View details for DOI 10.1016/j.jmps.2014.07.011

  View details for Web of Science ID 000343841900007

• Multifunctional Skin-Like Electronics for Quantitative, Clinical Monitoring of Cutaneous Wound Healing ADVANCED HEALTHCARE MATERIALS Hattori, Y., Falgout, L., Lee, W., Jung, S., Poon, E., Lee, J., Na, I., Geisler, A., Sadhwani, D., Zhang, Y., Su, Y., Wang, X., Liu, Z., Xia, J., Cheng, H., Webb, R., Bonifas, A. P., Won, P., Jeong, J., Jang, K., Song, Y., Nardone, B., Nodzenski, M., Fan, J. A., Huang, Y., West, D. P., Paller, A. S., Alam, M., Yeo, W., Rogers, J. A. 2014; 3 (10): 1597–1607

  Abstract

  Non-invasive, biomedical devices have the potential to provide important, quantitative data for the assessment of skin diseases and wound healing. Traditional methods either rely on qualitative visual and tactile judgments of a professional and/or data obtained using instrumentation with forms that do not readily allow intimate integration with sensitive skin near a wound site. Here, an electronic sensor platform that can softly and reversibly laminate perilesionally at wounds to provide highly accurate, quantitative data of relevance to the management of surgical wound healing is reported. Clinical studies on patients using thermal sensors and actuators in fractal layouts provide precise time-dependent mapping of temperature and thermal conductivity of the skin near the wounds. Analytical and simulation results establish the fundamentals of the sensing modalities, the mechanics of the system, and strategies for optimized design. The use of this type of "epidermal" electronics system in a realistic clinical setting with human subjects establishes a set of practical procedures in disinfection, reuse, and protocols for quantitative measurement. The results have the potential to address important unmet needs in chronic wound management.

  View details for DOI 10.1002/adhm.201400073

  View details for Web of Science ID 000343798800009

  View details for PubMedID 24668927

  View details for PubMedCentralID PMC4177017

• Materials and Designs for Wireless Epidermal Sensors of Hydration and Strain ADVANCED FUNCTIONAL MATERIALS Huang, X., Liu, Y., Cheng, H., Shin, W., Fan, J. A., Liu, Z., Lu, C., Kong, G., Chen, K., Patnaik, D., Lee, S., Hage-Ali, S., Huang, Y., Rogers, J. A. 2014; 24 (25): 3846–54

  View details for DOI 10.1002/adfm.201303886

  View details for Web of Science ID 000338011200001

• Experimental and Theoretical Studies of Serpentine Microstructures Bonded To Prestrained Elastomers for Stretchable Electronics ADVANCED FUNCTIONAL MATERIALS Zhang, Y., Wang, S., Li, X., Fan, J. A., Xu, S., Song, Y. M., Choi, K., Yeo, W., Lee, W., Nazaar, S. N., Lu, B., Yin, L., Hwang, K., Rogers, J. A., Huang, Y. 2014; 24 (14): 2028-2037

  View details for DOI 10.1002/adfm.201302957

  View details for Web of Science ID 000333809300008

• Fractal design concepts for stretchable electronics NATURE COMMUNICATIONS Fan, J. A., Yeo, W., Su, Y., Hattori, Y., Lee, W., Jung, S., Zhang, Y., Liu, Z., Cheng, H., Falgout, L., Bajema, M., Coleman, T., Gregoire, D., Larsen, R. J., Huang, Y., Rogers, J. A. 2014; 5

  Abstract

  Stretchable electronics provide a foundation for applications that exceed the scope of conventional wafer and circuit board technologies due to their unique capacity to integrate with soft materials and curvilinear surfaces. The range of possibilities is predicated on the development of device architectures that simultaneously offer advanced electronic function and compliant mechanics. Here we report that thin films of hard electronic materials patterned in deterministic fractal motifs and bonded to elastomers enable unusual mechanics with important implications in stretchable device design. In particular, we demonstrate the utility of Peano, Greek cross, Vicsek and other fractal constructs to yield space-filling structures of electronic materials, including monocrystalline silicon, for electrophysiological sensors, precision monitors and actuators, and radio frequency antennas. These devices support conformal mounting on the skin and have unique properties such as invisibility under magnetic resonance imaging. The results suggest that fractal-based layouts represent important strategies for hard-soft materials integration.

  View details for DOI 10.1038/ncomms4266

  View details for Web of Science ID 000332667600013

  View details for PubMedID 24509865

• Spectrally selective chiral silicon metasurfaces based on infrared Fano resonances. Nature communications Wu, C., Arju, N., Kelp, G., Fan, J. A., Dominguez, J., Gonzales, E., Tutuc, E., Brener, I., Shvets, G. 2014; 5: 3892-?

  Abstract

  Metamaterials and metasurfaces represent a remarkably versatile platform for light manipulation, biological and chemical sensing, and nonlinear optics. Many of these applications rely on the resonant nature of metamaterials, which is the basis for extreme spectrally selective concentration of optical energy in the near field. In addition, metamaterial-based optical devices lend themselves to considerable miniaturization because of their subwavelength features. This additional advantage sets metamaterials apart from their predecessors, photonic crystals, which achieve spectral selectivity through their long-range periodicity. Unfortunately, spectral selectivity of the overwhelming majority of metamaterials that are made of metals is severely limited by high plasmonic losses. Here we propose and demonstrate Fano-resonant all-dielectric metasurfaces supporting optical resonances with quality factors Q>100 that are based on CMOS-compatible materials: silicon and its oxide. We also demonstrate that these infrared metasurfaces exhibit extreme planar chirality, opening exciting possibilities for efficient ultrathin circular polarizers and narrow-band thermal emitters of circularly polarized radiation.

  View details for DOI 10.1038/ncomms4892

  View details for PubMedID 24861488

• Ultrasmooth, Highly Spherical Monocrystalline Gold Particles for Precision Plasmonics ACS NANO Lee, Y., Schade, N. B., Sun, L., Fan, J. A., Bae, D. R., Mariscal, M. M., Lee, G., Capasso, F., Sacanna, S., Manoharan, V. N., Yi, G. 2013; 7 (12): 11064-11070

  Abstract

  Ultrasmooth, highly spherical monocrystalline gold particles were prepared by a cyclic process of slow growth followed by slow chemical etching, which selectively removes edges and vertices. The etching process effectively makes the surface tension isotropic, so that spheres are favored under quasi-static conditions. It is scalable up to particle sizes of 200 nm or more. The resulting spherical crystals display uniform scattering spectra and consistent optical coupling at small separations, even showing Fano-like resonances in small clusters. The high monodispersity of the particles we demonstrate should facilitate the self-assembly of nanoparticle clusters with uniform optical resonances, which could in turn be used to fabricate optical metafluids. Narrow size distributions are required to control not only the spectral features but also the morphology and yield of clusters in certain assembly schemes.

  View details for DOI 10.1021/nn404765w

  View details for Web of Science ID 000329137100067

  View details for PubMedID 24219591

• Mechanics of ultra-stretchable self-similar serpentine interconnects ACTA MATERIALIA Zhang, Y., Fu, H., Su, Y., Xu, S., Cheng, H., Fan, J. A., Hwang, K., Rogers, J. A., Huang, Y. 2013; 61 (20): 7816–27

  View details for DOI 10.1016/j.actamat.2013.09.020

  View details for Web of Science ID 000328179700028

• Tetrahedral Colloidal Clusters from Random Parking of Bidisperse Spheres PHYSICAL REVIEW LETTERS Schade, N. B., Holmes-Cerfon, M. C., Chen, E. R., Aronzon, D., Collins, J. W., Fan, J. A., Capasso, F., Manoharan, V. N. 2013; 110 (14)

  View details for DOI 10.1103/PhysRevLett.110.148303

  View details for Web of Science ID 000317190100008

• Stretchable batteries with self-similar serpentine interconnects and integrated wireless recharging systems NATURE COMMUNICATIONS Xu, S., Zhang, Y., Cho, J., Lee, J., Huang, X., Jia, L., Fan, J. A., Su, Y., Su, J., Zhang, H., Cheng, H., Lu, B., Yu, C., Chuang, C., Kim, T., Song, T., Shigeta, K., Kang, S., Dagdeviren, C., Petrov, I., Braun, P. V., Huang, Y., Paik, U., Rogers, J. A. 2013; 4

  Abstract

  An important trend in electronics involves the development of materials, mechanical designs and manufacturing strategies that enable the use of unconventional substrates, such as polymer films, metal foils, paper sheets or rubber slabs. The last possibility is particularly challenging because the systems must accommodate not only bending but also stretching. Although several approaches are available for the electronics, a persistent difficulty is in power supplies that have similar mechanical properties, to allow their co-integration with the electronics. Here we introduce a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual 'self-similar' interconnect structures between them. The result enables reversible levels of stretchability up to 300%, while maintaining capacity densities of ~1.1 mAh cm(-2). Stretchable wireless power transmission systems provide the means to charge these types of batteries, without direct physical contact.

  View details for DOI 10.1038/ncomms2553

  View details for Web of Science ID 000316616400111

  View details for PubMedID 23443571

• Plasmonic Mode Engineering with Templated Self-Assembled Nanoclusters NANO LETTERS Fan, J. A., Bao, K., Sun, L., Bao, J., Manoharan, V. N., Nordlander, P., Capasso, F. 2012; 12 (10): 5318-5324

  Abstract

  Plasmonic nanoparticle assemblies are a materials platform in which optical modes, resonant frequencies, and near-field intensities can be specified by the number and position of nanoparticles in a cluster. A current challenge is to achieve clusters with higher yields and new types of shapes. In this Letter, we show that a broad range of plasmonic nanoshell nanoclusters can be assembled onto a lithographically defined elastomeric substrate with relatively high yields using templated assembly. We assemble and measure the optical properties of three cluster types: Fano-resonant heptamers, linear chains, and rings of nanoparticles. The yield of heptamer clusters is measured to be over 30%. The assembly of plasmonic nanoclusters on an elastomer paves the way for new classes of plasmonic nanocircuits and colloidal metamaterials that can be transfer-printed onto various substrate media.

  View details for DOI 10.1021/nl302650t

  View details for Web of Science ID 000309615000041

  View details for PubMedID 22947109

• Near-Normal Incidence Dark-Field Microscopy: Applications to Nanoplasmonic Spectroscopy NANO LETTERS Fan, J. A., Bao, K., Lassiter, J. B., Bao, J., Halas, N. J., Nordlander, P., Capasso, F. 2012; 12 (6): 2817-2821

  Abstract

  The spectroscopic characterization of individual nanostructures is of fundamental importance to understanding a broad range of physical and chemical processes. One general and powerful technique that addresses this aim is dark-field microscopy, with which the scattered light from an individual structure can be analyzed with minimal background noise. We present the spectroscopic analysis of individual plasmonic nanostructures using dark-field illumination with incidence nearly normal to the substrate. We show that, compared to large incidence angle approaches, the near-normal incidence approach provides significantly higher signal-to-background ratios and reduced retardation field effects. To demonstrate the utility of this technique, we characterize an individual chemically synthesized gold nanoshell and a lithographically defined heptamer exhibiting a pronounced Fano-like resonance. We show that the line shape of the latter strongly depends on the incidence angle. Near-normal incidence dark-field microscopy can be used to characterize a broad range of molecules and nanostructures and can be adapted to most microscopy setups.

  View details for DOI 10.1021/nl300160y

  View details for Web of Science ID 000305106400028

  View details for PubMedID 22524322

• DNA-Enabled Self-Assembly of Plasmonic Nanoclusters NANO LETTERS Fan, J. A., He, Y., Bao, K., Wu, C., Bao, J., Schade, N. B., Manoharan, V. N., Shvets, G., Nordlander, P., Liu, D. R., Capasso, F. 2011; 11 (11): 4859-4864

  Abstract

  DNA nanotechnology provides a versatile foundation for the chemical assembly of nanostructures. Plasmonic nanoparticle assemblies are of particular interest because they can be tailored to exhibit a broad range of electromagnetic phenomena. In this Letter, we report the assembly of DNA-functionalized nanoparticles into heteropentamer clusters, which consist of a smaller gold sphere surrounded by a ring of four larger spheres. Magnetic and Fano-like resonances are observed in individual clusters. The DNA plays a dual role: it selectively assembles the clusters in solution and functions as an insulating spacer between the conductive nanoparticles. These particle assemblies can be generalized to a new class of DNA-enabled plasmonic heterostructures that comprise various active and passive materials and other forms of DNA scaffolding.

  View details for DOI 10.1021/nl203194m

  View details for Web of Science ID 000296674700062

  View details for PubMedID 22007607

• Dipolar modeling and experimental demonstration of multi-beam plasmonic collimators NEW JOURNAL OF PHYSICS Tetienne, J., Blanchard, R., Yu, N., Genevet, P., Kats, M. A., Fan, J. A., Edamura, T., Furuta, S., Yamanishi, M., Capasso, F. 2011; 13

  View details for DOI 10.1088/1367-2630/13/5/053057

  View details for Web of Science ID 000292002900005

• Terahertz plasmonics ELECTRONICS LETTERS Yu, N., Wang, Q. J., Kats, M. A., Fan, J. A., Capasso, F., Khanna, S. P., Li, L., Davies, A. G., Linfield, E. H. 2010; 46 (26): S52–S57

  View details for DOI 10.1049/el.2010.2131

  View details for Web of Science ID 000286053000020

• Fano-like Interference in Self-Assembled Plasmonic Quadrumer Clusters NANO LETTERS Fan, J. A., Bao, K., Wu, C., Bao, J., Bardhan, R., Halas, N. J., Manoharan, V. N., Shvets, G., Nordlander, P., Capasso, F. 2010; 10 (11): 4680-4685

  Abstract

  Assemblies of strongly interacting metallic nanoparticles are the basis for plasmonic nanostructure engineering. We demonstrate that clusters of four identical spherical particles self-assembled into a close-packed asymmetric quadrumer support strong Fano-like interference. This feature is highly sensitive to the polarization of the incident electric field due to orientation-dependent coupling between particles in the cluster. This structure demonstrates how careful design of self-assembled colloidal systems can lead to the creation of new plasmonic modes and the enabling of interference effects in plasmonic systems.

  View details for DOI 10.1021/nl1029732

  View details for Web of Science ID 000283907600065

  View details for PubMedID 20923179

• GaAs/Al0.15Ga0.85As terahertz quantum cascade lasers with double-phonon resonant depopulation operating up to 172 K APPLIED PHYSICS LETTERS Adams, R. W., Vijayraghavan, K., Wang, Q., Fan, J., Capasso, F., Khanna, S. P., Davies, A., Linfield, E. H., Belkin, M. A. 2010; 97 (13)

  View details for DOI 10.1063/1.3496035

  View details for Web of Science ID 000282443800011

• Designer spoof surface plasmon structures collimate terahertz laser beams NATURE MATERIALS Yu, N., Wang, Q. J., Kats, M. A., Fan, J. A., Khanna, S. P., Li, L., Davies, A. G., Linfield, E. H., Capasso, F. 2010; 9 (9): 730-735

  Abstract

  Surface plasmons have found a broad range of applications in photonic devices at visible and near-infrared wavelengths. In contrast, longer-wavelength surface electromagnetic waves, known as Sommerfeld or Zenneck waves, are characterized by poor confinement to surfaces and are therefore difficult to control using conventional metallo-dielectric plasmonic structures. However, patterning the surface with subwavelength periodic features can markedly reduce the asymptotic surface plasmon frequency, leading to 'spoof' surface plasmons with subwavelength confinement at infrared wavelengths and beyond, which mimic surface plasmons at much shorter wavelengths. We demonstrate that by directly sculpting designer spoof surface plasmon structures that tailor the dispersion of terahertz surface plasmon polaritons on the highly doped semiconductor facets of terahertz quantum cascade lasers, the performance of the lasers can be markedly enhanced. Using a simple one-dimensional grating design, the beam divergence of the lasers was reduced from approximately 180 degrees to approximately 10 degrees, the directivity was improved by over 10 decibels and the power collection efficiency was increased by a factor of about six compared with the original unpatterned devices. We achieve these improvements without compromising high-temperature performance of the lasers.

  View details for DOI 10.1038/NMAT2822

  View details for Web of Science ID 000281178400023

  View details for PubMedID 20693995

• Fano Resonances in Plasmonic Nanoclusters: Geometrical and Chemical Tunability NANO LETTERS Lassiter, J., Sobhani, H., Fan, J. A., Kundu, J., Capasso, F., Nordlander, P., Halas, N. J. 2010; 10 (8): 3184–89

  Abstract

  Clusters of plasmonic nanoparticles and nanostructures support Fano resonances. Here we show that this spectral feature, produced by the interference between bright and dark modes of the nanoparticle cluster, is strongly dependent upon both geometry and local dielectric environment. This permits a highly sensitive tunability of the Fano dip in both wavelength and amplitude by varying cluster dimensions, geometry, and relative size of the individual nanocluster components. Plasmonic nanoclusters show an unprecedented sensitivity to dielectric environment with a local surface plasmon resonance figure of merit of 5.7, the highest yet reported for localized surface plasmon resonance sensing in a finite nanostructure.

  View details for DOI 10.1021/nl102108u

  View details for Web of Science ID 000280728900076

  View details for PubMedID 20698635

• Self-Assembled Plasmonic Nanoparticle Clusters SCIENCE Fan, J. A., Wu, C., Bao, K., Bao, J., Bardhan, R., Halas, N. J., Manoharan, V. N., Nordlander, P., Shvets, G., Capasso, F. 2010; 328 (5982): 1135-1138

  Abstract

  The self-assembly of colloids is an alternative to top-down processing that enables the fabrication of nanostructures. We show that self-assembled clusters of metal-dielectric spheres are the basis for nanophotonic structures. By tailoring the number and position of spheres in close-packed clusters, plasmon modes exhibiting strong magnetic and Fano-like resonances emerge. The use of identical spheres simplifies cluster assembly and facilitates the fabrication of highly symmetric structures. Dielectric spacers are used to tailor the interparticle spacing in these clusters to be approximately 2 nanometers. These types of chemically synthesized nanoparticle clusters can be generalized to other two- and three-dimensional structures and can serve as building blocks for new metamaterials.

  View details for DOI 10.1126/science.1187949

  View details for Web of Science ID 000278104700037

  View details for PubMedID 20508125

• Influence of excitation and collection geometry on the dark field spectra of individual plasmonic nanostructures OPTICS EXPRESS Knight, M. W., Fan, J., Capasso, F., Halas, N. J. 2010; 18 (3): 2579–87

  Abstract

  Dark field microspectroscopy is the primary method for the study of plasmon modes of individual metallic nanostructures. Light from a plasmonic nanostructure typically scatters with a strong angular and modal dependence, resulting in significant variations in the observed spectral response depending on excitation and collection angle and polarization of incident light. Here we examine how spectrally dependent radiation patterns arising from an individual plasmonic nanoparticle, positioned on a dielectric substrate, affect the detection of its plasmon modes. Careful consideration of excitation and collection geometry is of critical concern in quantitative studies of the optical response of these nanoparticle systems.

  View details for DOI 10.1364/OE.18.002579

  View details for Web of Science ID 000274791200080

  View details for PubMedID 20174087

• Layered superconductors as negative-refractive-index metamaterials PHYSICAL REVIEW B Rakhmanov, A. L., Yampol'skii, V. A., Fan, J. A., Capasso, F., Nori, F. 2010; 81 (7)

  View details for DOI 10.1103/PhysRevB.81.075101

  View details for Web of Science ID 000274998200030

• Plasmonics for Laser Beam Shaping IEEE TRANSACTIONS ON NANOTECHNOLOGY Yu, N., Blanchard, R., Fan, J., Wang, Q., Pfluegl, C., Diehl, L., Edamura, T., Furuta, S., Yamanishi, M., Kan, H., Capasso, F. 2010; 9 (1): 11–29

  View details for DOI 10.1109/TNANO.2009.2029099

  View details for Web of Science ID 000275725000003

• Quantum cascade lasers with integrated plasmonic antenna-array collimators OPTICS EXPRESS Yu, N., Blanchard, R., Fan, J., Wang, Q., Pfluegl, C., Diehl, L., Edamura, T., Yamanishi, M., Kan, H., Capasso, F. 2008; 16 (24): 19447–61

  Abstract

  We demonstrated in simulations and experiments that by defining a properly designed two-dimensional metallic aperture-grating structure on the facet of quantum cascade lasers, a small beam divergence angle can be achieved in directions both perpendicular and parallel to the laser waveguide layers (denoted as theta perpendicular and theta parallel, respectively). Beam divergence angles as small as theta perpendicular=2.7 degrees and theta parallel=3.7 degrees have been demonstrated. This is a reduction by a factor of approximately 30 and approximately 10, respectively, compared to those of the original lasers emitting at a wavelength of 8.06 microm. The devices preserve good room temperature performance with output power as high as approximately 55% of that of the original unpatterned lasers. We studied in detail the trade-off between beam divergence and power throughput for the fabricated devices. We demonstrated plasmonic collimation for buried heterostructure lasers and ridge lasers; devices with different waveguide structures but with the same plasmonic collimator design showed similar performance. We also studied a device patterned with a "spider's web" pattern, which gives us insight into the distribution of surface plasmons on the laser facet.

  View details for DOI 10.1364/OE.16.019447

  View details for Web of Science ID 000261561900006

  View details for PubMedID 19030032

• Small divergence edge-emitting semiconductor lasers with two-dimensional plasmonic collimators APPLIED PHYSICS LETTERS Yu, N., Blanchard, R., Fan, J., Capasso, F., Edamura, T., Yamanishi, M., Kan, H. 2008; 93 (18)

  View details for DOI 10.1063/1.3009599

  View details for Web of Science ID 000260778100001

• Small-divergence semiconductor lasers by plasmonic collimation NATURE PHOTONICS Yu, N., Fan, J., Wang, Q. J., Pfluegl, C., Diehl, L., Edamura, T., Yamanishi, M., Kan, H., Capasso, F. 2008; 2 (9): 564-570

  View details for DOI 10.1038/nphoton.2008.152

  View details for Web of Science ID 000259232300019

• Terahertz quantum cascade lasers with copper metal-metal waveguides operating up to 178 K OPTICS EXPRESS Belkin, M. A., Fan, J. A., Hormoz, S., Capasso, F., Khanna, S. P., Lachab, M., Davies, A., Linfield, E. H. 2008; 16 (5): 3242–48

  Abstract

  We report terahertz quantum cascade lasers operating in pulsed mode at an emission frequency of 3 THz and up to a maximum temperature of 178 K. The improvement in the maximum operating temperature is achieved by using a three-quantum-well active region design with resonant-phonon depopulation and by utilizing copper, instead of gold, for the cladding material in the metal-metal waveguides.

  View details for DOI 10.1364/OE.16.003242

  View details for Web of Science ID 000254121300043

  View details for PubMedID 18542411

• Wide-ridge metal-metal terahertz quantum cascade lasers with high-order lateral mode suppression APPLIED PHYSICS LETTERS Fan, J. A., Belkin, M. A., Capasso, F., Khanna, S. P., Lachab, M., Davies, A., Linfield, E. H. 2008; 92 (3)

  View details for DOI 10.1063/1.2835202

  View details for Web of Science ID 000252718600006

• Double-metal waveguide lambda similar or equal to 19 mu m quantum cascade lasers grown by metal organic vapour phase epitaxy ELECTRONICS LETTERS Fan, J. A., Belkin, M. A., Troccoli, M., Corzine, S., Bour, D., Hoefler, G., Capasso, F. 2007; 43 (23): 1284–85

  View details for DOI 10.1049/el:20072450

  View details for Web of Science ID 000251759200027

• Plasmonic nanoclusters: a path towards negative-index metafluids OPTICS EXPRESS Urzhumov, Y. A., Shvets, G., Fan, J., Capasso, F., Brandl, D., Nordlander, P. 2007; 15 (21): 14129–45

  Abstract

  We introduce the concept of metafluids-liquid metamaterials based on clusters of metallic nanoparticles which we will term Artificial Plasmonic Molecules (APMs). APMs comprising four nanoparticles in a tetrahedral arrangement have isotropic electric and magnetic responses and are analyzed using the plasmon hybridization (PH) method, an electrostatic eigenvalue equation, and vectorial finite element frequency domain (FEFD) electromagnetic simulations. With the aid of group theory, we identify the resonances that provide the strongest electric and magnetic response and study them as a function of separation between spherical nanoparticles. It is demonstrated that a colloidal solution of plasmonic tetrahedral nanoclusters can act as an optical medium with very large, small, or even negative effective permittivity, epsilon(eff), and substantial effective magnetic susceptibility, Chi(eff) = mu(eff) -1, in the visible or near infrared bands. We suggest paths for increasing the magnetic response, decreasing the damping, and developing a metafluid with simultaneously negative epsilon(eff) and mu(eff).

  View details for DOI 10.1364/OE.15.014129

  View details for Web of Science ID 000251223100071

  View details for PubMedID 19550686

• Single-mode laser action in quantum cascade lasers with spiral-shaped chaotic resonators APPLIED PHYSICS LETTERS Audet, R., Belkin, M. A., Fan, J. A., Lee, B. G., Lin, K., Capasso, F. 2007; 91 (13)

  View details for DOI 10.1063/1.2784290

  View details for Web of Science ID 000249787000006

• Surface emitting terahertz quantum cascade laser with a double-metal waveguide OPTICS EXPRESS Fan, J. A., Belkin, M. A., Capasso, F., Khanna, S., Lachab, M., Davies, A., Linfield, E. H. 2006; 14 (24): 11672–80

  Abstract

  We investigate the implementation of surface emission via a second order grating in terahertz quantum cascade lasers with double-metal waveguides. Absorbing edge structures are designed to enforce anti-reflecting boundary conditions, which ensure distributed feedback in the cavity. The grating duty cycle is chosen in order to maximize slope efficiency. Fabricated devices demonstrate surface emission output powers that are comparable to those measured from edge-emitting double metal waveguide structures without gratings. The slope efficiency of surface emitting lasers is twice that of double-metal edge emitting structures. Surface emitting lasers show single mode behavior, with a beam divergence of approximately six degrees.

  View details for DOI 10.1364/OE.14.011672

  View details for Web of Science ID 000242325700021

  View details for PubMedID 19529587