Jennifer Dionne

All Publications

• Atomic-Scale Moiré and Electronic Structure Analysis of Twisted Epitaxial MoS2-Au-MoS2 Heterostructures. Nano letters Cui, Y., Xu, K., Ren, P., Yuan, L., Czaja, P., Barnum, A., Sarkar, P., Altman, A., Bustillo, K., Kundu, S., Ramdas, A., Wang, X., Wan, G., Wang, Y., Wang, J., Song, C., Lim, C., Zheng, Q., Yao, H., Heinz, T., Hwang, H. Y., Majumdar, A., Dionne, J. A., Ophus, C., da Jornada, F. H., Sinclair, R., Cui, Y. 2026

  Abstract

  Twisted epitaxy enables precise orientation control of nanostructures confined within van der Waals (vdW) gaps. Here, we investigate the moiré and electronic structure of a representative twisted epitaxial system, where Au nanodiscs are grown inside twisted bilayer MoS2 with a 6° interlayer twist, inducing a 3° symmetrical misalignment of Au relative to each MoS2 layer (MoS2-Au-MoS2). Using multislice electron ptychography (MEP), we resolve the three-dimensional "moiré-of-moirés" structure of MoS2-Au-MoS2 with atomic resolution. Electron energy loss spectroscopy (EELS) shows that MoS2 encapsulation significantly reduces the plasmon energy of Au nanodiscs compared with their unencapsulated counterparts. Furthermore, first-principles calculations reveal that Au insertion alters the electronic band alignment near the Fermi level of bilayer MoS2. Our results introduce a twisted MoS2-Au-MoS2 heterostructure as a structurally and electronically rich material system and establish twisted epitaxy as a new strategy for moiré engineering and the synthesis of 2D-confined materials with tunable optoelectronic properties.

  View details for DOI 10.1021/acs.nanolett.5c04205

  View details for PubMedID 41705938

• A Humidity-Tolerant Photocatalyst for Methane Removal. Environmental science & technology Kessler, M. I., Randall, R., Wan, G., Xu, K., Zhang, Y., Dionne, J. A., Jackson, R. B., Majumdar, A. 2026

  Abstract

  To mitigate the climate impacts of methane, there has been substantial interest in the complete oxidation of methane to carbon dioxide by using photocatalysis at ambient temperatures. However, previous studies have primarily examined methane concentrations well above those found at most emission sources and have overlooked the role of realistic humidity. This work reports methane oxidation rates at 25 °C for oxide-based photocatalysts for methane concentrations ranging from 2 to 5000 ppm. Even under dry conditions with less than 2% relative humidity, residual water attracted to the hydrophilic surfaces of these photocatalysts severely inhibits methane oxidation. Thinning this water layer boosts methane oxidation rates by up to 1 order of magnitude. Furthermore, surface modification of titanium dioxide with a hydrophobic fluorosilane coating (1H,1H,2H,2H-perfluorooctyltriethoxysilane) enables room temperature photocatalytic removal of dilute methane even under conditions with up to 80% relative humidity. These findings and engineering solutions offer guidance for the development of light-driven approaches for scalable methane removal.

  View details for DOI 10.1021/acs.est.5c16764

  View details for PubMedID 41665929

• Twisted Tin-Chloride Perovskite Single-Crystal Heterostructures. Angewandte Chemie (International ed. in English) Cleron, J. L., Chen, C. Y., Pan, F., Saha, S., Marlton, F. P., Stolz, R. M., Li, J., Dionne, J. A., Liu, F., Filip, M. R., Karunadasa, H. I. 2025: e20140

  Abstract

  Self-assembly affords simpler synthetic routes to heterostructures compared with manual layer-by-layer stacking, yet controlling interlayer twist angles in a bulk solid remains an outstanding challenge. We report two new single-crystal heterostructures: (Sn2Cl2)(CYS)2SnCl4 (CYS = +NH3(CH2)2S-; Sn_CYS) and (Sn2Cl2)(SeCYS)2SnCl4 (SeCYS = +NH3(CH2)2Se-; Sn_SeCYS) synthesized in solution, with alternating perovskite and intergrowth layers. Notably, compared to the recently reported lead analog, (Pb2Cl2)(CYS)2PbCl4 (Pb_CYS), the tin heterostructures feature a twist between the perovskite and intergrowth layers. We trace this twist to local distortions at the Sn centers, which change the interfacial lattice-matching requirements compared to those of the Pb analog. Electronic band structure calculations show that the striking differences in the relative energies of perovskite- and intergrowth-derived bands in Sn_CYS and Pb_CYS arise from structural and not compositional differences. The structural anisotropy of Sn_CYS is also reflected in a large in-plane photoluminescence linear anisotropy ratio. Interfacial strain further affords differential incorporation of Pb into the perovskite and intergrowth layers of the Sn heterostructures, resulting in redshifted optical absorption onsets. Thus, we posit that local structural distortions may be exploited to manipulate the twist angle and interfacial strain in bulk heterostructures, providing a new handle for tuning the band alignments of bulk quantum-well electronic structures.

  View details for DOI 10.1002/anie.202520140

  View details for PubMedID 41414937

• Atmospheric-pressure ammonia synthesis on AuRu catalysts enabled by plasmon-controlled hydrogenation and nitrogen-species desorption NATURE ENERGY Yuan, L., Bourgeois, B. B., Begin, E., Zhang, Y., Dai, A. X., Cheng, Z., Mckeown-Green, A. S., Xue, Z., Cui, Y., Xu, K., Wang, Y., Jones, M. R., Majumdar, A., Bao, J., Dionne, J. A. 2025

  View details for DOI 10.1038/s41560-025-01911-9

  View details for Web of Science ID 001632097400001

• Room-temperature valley-selective emission in Si-MoSe2 heterostructures enabled by high-quality-factor chiroptical cavities. Nature communications Pan, F., Li, X., Johnson, A. C., Dhuey, S., Saunders, A., Hu, M. X., Dixon, J. P., Dagli, S., Lau, S. C., Weng, T., Chen, C. Y., Zeng, J. H., Apte, R., Heinz, T. F., Liu, F., Deng, Z. L., Dionne, J. A. 2025

  Abstract

  Transition metal dichalcogenides possess valley pseudospin, enabling coupling between photon spin and electron spin for classical and quantum information processing. However, rapid valley-dephasing processes have impeded the development of scalable, high-performance valleytronic devices operating at room temperature. Here we demonstrate that a chiral resonant metasurface can enable room-temperature valley-selective emission in MoSe2 monolayers independent of excitation polarization. This platform provides circular eigen-polarization states with a high quality factor (Q-factor) and strong chiral near-field enhancement. The fabricated Si chiral metasurfaces exhibit chiroptical resonances with Q-factors up to 450 at visible wavelengths. We reveal degrees of circular polarization (DOP) reaching a record high of 0.5 at room temperature. Our measurements show that the high DOP can be attributed to the significantly increased chiroptical local density of states, which enhances valley-specific radiative transition rates by a factor of ~13. Our work could facilitate the development of ultracompact chiral classical and quantum light sources.

  View details for DOI 10.1038/s41467-025-66502-4

  View details for PubMedID 41318601

• Resonant metasurface-enabled quantum light sources for single-photon emission and entangled photon-pair generation. Nanophotonics (Berlin, Germany) Pan, F., Bordoloi, P., Chen, C. Y., Dionne, J. A. 2025; 14 (23): 3861-3870

  Abstract

  Light encodes information in multiple degrees of freedom (e.g., frequency, amplitude, and phase), enabling high-speed, high-bandwidth communication through fiber optics. Unlike classical light, quantum light (single or entangled photons) can transmit quantum states over long distances without loss of coherence, thereby coherently interconnecting quantum nodes for distributed quantum entanglement. Quantum light sources are critical for developing scalable quantum networks aimed at distributed quantum computing, quantum teleportation, and secure quantum communications. However, existing quantum light sources suffer from limited integrability, insufficient spectral and spatial tunability, and inefficiencies in achieving mass-produced, deterministic, on-demand quantum light generation. These limitations significantly hinder progress toward direct, on-chip integration with quantum processing units and detectors - an essential step toward scalable quantum networks. Resonant metasurfaces that leverage photonic modes - such as Mie resonances, guided-mode resonances, or symmetry-protected bound states in the continuum - offer strong spatial and temporal confinement of electromagnetic fields, characterized by high quality factors and small mode volumes. These metasurfaces greatly enhance linear and nonlinear light-matter interactions, making them ideal for efficient on-chip quantum light generation and manipulation. Here, we describe recent advances in nanoscale quantum light sources and quantum photonic state manipulation enabled by resonant metasurfaces. We also provide an outlook on next-generation miniaturized quantum light sources achievable through materials innovations in quantum emitters, the co-design of resonant metasurfaces, and ultimately, the heterogeneous integration of emerging layered van der Waals materials with resonant metasurfaces.

  View details for DOI 10.1515/nanoph-2025-0196

  View details for PubMedID 41246496

  View details for PubMedCentralID PMC12617726

• Integrative Approaches to Reveal Catalyst Dynamics: Bridging Operando Techniques, Theory, and Artificial Intelligence. ACS nano Lee, T. H., Lee, S., Yuan, L., Dionne, J. A., Park, J. 2025

  Abstract

  Catalysts operate under complex conditions that require sophisticated approaches to understand their dynamics. This perspective outlines advances in experimental operando techniques, theoretical approaches, and machine learning (ML)-based data analysis to elucidate catalyst dynamics and improve the next-generation catalyst design. We first survey operando techniques, spanning electron microscopy, X-ray spectroscopy, and vibrational spectroscopy, that capture catalyst dynamics under operating conditions. We then discuss how operando observations integrate with and inform theoretical models, creating an iterative feedback loop between experiment and computation. Finally, we highlight how advanced data analysis, especially ML, enables the interpretation of high-dimensional operando data sets and can even inform catalyst design. Together, these synergetic approaches provide a unified framework for probing catalyst function and accelerating the rational design of efficient, durable catalytic systems for sustainable chemical manufacturing.

  View details for DOI 10.1021/acsnano.5c10976

  View details for PubMedID 41099495

• Upconverting microgauges reveal intraluminal force dynamics in vivo. ArXiv Casar, J. R., McLellan, C. A., Shi, C., Stiber, A., Lay, A., Siefe, C., Parakh, A., Gaerlan, M., Gu, W., Goodman, M. B., Dionne, J. A. 2025

  Abstract

  The forces generated by action potentials in muscle cells shuttle blood, food, and waste products throughout the body's luminal structures. While non-invasive electrophysiological techniques exist,1-3 most mechanosensitive tools cannot access luminal structures non-invasively.4-6 Here, we create non-toxic, ingestible mechanosensors to enable the quantitative study of luminal forces and apply them to study feeding in living Caenorhabditis elegans roundworms. These optical "microgauges" comprise upconverting NaY0.8Yb0.18Er0.02F4@NaYF4 nanoparticles (UCNPs) embedded in polystyrene microspheres. Combining optical microscopy and atomic force microscopy to study microgauges in vitro, we show that force evokes a linear and hysteresis-free change in the ratio of emitted red to green light. With fluorescence imaging and non-invasive electrophysiology, we show that adult C. elegans generate bite forces during feeding on the order of 10 μN and that the temporal pattern of force generation is aligned with muscle activity in the feeding organ. Moreover, the bite force we measure corresponds to Hertzian contact stresses within the pressure range used to lyse the worm's bacterial food.7,8 Microgauges have the potential to enable quantitative studies that investigate how neuromuscular stresses are affected by aging, genetic mutations, and drug treatments in this and other luminal organs.

  View details for DOI 10.2172/6417825

  View details for PubMedID 41281229

  View details for PubMedCentralID PMC12632686

• Upconverting microgauges reveal intraluminal force dynamicsin vivo. ArXiv Casar, J. R., McLellan, C. A., Shi, C., Stiber, A., Lay, A., Siefe, C., Parakh, A., Gaerlan, M., Gu, W., Goodman, M. B., Dionne, J. A. 2025

  Abstract

  The forces generated by action potentials in muscle cells shuttle blood, food, and waste products throughout the body's luminal structures. While non-invasive electrophysiological techniques exist,1-3 most mechanosensitive tools cannot access luminal structures non-invasively.4-6 Here, we create non-toxic, ingestible mechanosensors to enable the quantitative study of luminal forces and apply them to study feeding in living Caenorhabditis elegans roundworms. These optical "microgauges" comprise upconverting NaY0.8Yb0.18Er0.02F4@NaYF4 nanoparticles (UCNPs) embedded in polystyrene microspheres. Combining optical microscopy and atomic force microscopy to study microgauges in vitro, we show that force evokes a linear and hysteresis-free change in the ratio of emitted red to green light. With fluorescence imaging and non-invasive electrophysiology, we show that adult C. elegans generate bite forces during feeding on the order of 10 muN and that the temporal pattern of force generation is aligned with muscle activity in the feeding organ. Moreover, the bite force we measure corresponds to Hertzian contact stresses within the pressure range used to lyse the worm's bacterial food.7,8 Microgauges have the potential to enable quantitative studies that investigate how neuromuscular stresses are affected by aging, genetic mutations, and drug treatments in this and other luminal organs.

  View details for PubMedID 41281229

• Resonant metasurface-enabled quantum light sources for single-photon emission and entangled photon-pair generation NANOPHOTONICS Pan, F., Bordoloi, P., Chen, C., Dionne, J. A. 2025

  View details for DOI 10.1515/nanoph-2025-0196

  View details for Web of Science ID 001570301100001

• The Next 25 Years of Nanoscience and Nanotechnology: A <i>Nano Letters</i> Roadmap NANO LETTERS Shim, W., Natelson, D., Arbiol, J., Besley, E., Dionne, J. A., Herrmann, C., Jariwala, D., Lau, C., Li, L., Manna, L., Nam, K., Nie, G., Prieto, A. L., Tee, B. C. K., van der Zande, A. M., Venkataraman, L., Wang, H., Wang, Y., Xiong, Q., Zhu, J., Odom, T. W. 2025; 25 (34): 12789-12798

  View details for DOI 10.1021/acs.nanolett.5c04115

  View details for Web of Science ID 001560555600001

  View details for PubMedID 40859733

• Low-energy nuclear fusion boosted by electrochemistry NATURE McKeown-Green, A., Dionne, J. A. 2025; 644 (8077): 614-615

  View details for DOI 10.1038/d41586-025-02254-x

  View details for Web of Science ID 001554868400023

• GHz-Speed Wavefront Shaping Metasurface Modulators Enabled by Resonant Electro-Optic Nanoantennas. Advanced materials (Deerfield Beach, Fla.) Dagli, S., Shim, J., Carr Delgado, H., Balch, H. B., Abdollahramezani, S., Chen, C. Y., Dolia, V., Klopfer, E., Dixon, J., Hu, J., Ogunlade, B., Song, J. H., Brongersma, M. L., Barton, D., Dionne, J. A. 2025: e06790

  Abstract

  Electrically tunable metasurfaces that control the amplitude and phase of light through biasing of nanoscale antennas present a route to compact modulator devices. However, most platforms face limitations in bandwidth, optical efficiency, and tuning response. Electro-optically tunable metasurfaces achieving both GHz amplitude modulation and transmissive wavefront shaping in the telecom range are presented. The resonant electro-optic nanoantenna design consists of a silicon nanobar atop thin-film lithium niobate, with gold electrodes. The nanobar is a periodically perturbed optical waveguide that supports high quality factor (Q > 1000) guided mode resonances excited with free-space light. Voltage biasing the lithium niobate tunes its refractive index, modulating the resonance of the nanobar through evanescent mode overlap. Absolute transmittance modulation of 7.1% with ±5 V applied voltage is demonstrated, and the modulation dependence on the resonance quality factor is shown. Additionally, the modulation bandwidth of these devices exceeds 800 MHz, and the electrode limitations on this bandwidth are studied. Finally, how this resonant antenna platform can enable wavefront shaping metasurfaces is shown. A beamsplitting metasurface device is demonstrated, whose diffraction efficiency can be modulated with a bandwidth of 1.03 GHz. The high-speed modulation and wavefront control capabilities of this platform provide a foundation for compact, high-bandwidth free-space communications and sensing devices.

  View details for DOI 10.1002/adma.202506790

  View details for PubMedID 40714801

• Catalight-An Open-Source Automated Photocatalytic Reactor Package Illustrated through Plasmonic Acetylene Hydrogenation JOURNAL OF PHYSICAL CHEMISTRY A Bourgeois, B. B., Dai, A. X., Carlin, C. C., Yuan, L., Al-Zubeidi, A., Cheng, W., Swearer, D. F., Dionne, J. A. 2025: 6170-6178

  Abstract

  An open-source and modular Python package, Catalight, is developed and demonstrated to automate (photo)catalysis measurements. (Photo)catalysis experiments require studying several parameters to evaluate performance, including the temperature, gas flow rate and composition, illumination power, and spectral profile. Catalight orchestrates measurements over this complicated parameter space and systematically stores, analyzes, and visualizes the results. To showcase the capabilities of Catalight, we perform an automated apparent activation barrier measurement of acetylene hydrogenation over a plasmonic AuPd catalyst on an Al2O3 support, simultaneously varying laser power, wavelength, and temperature in a multiday experiment controlled by a simple Python script. Our chemical results unexpectedly show an increased activation barrier upon light excitation, contrary to previous findings for other plasmonic reactions and catalysts. We show that the reaction rate order with respect to both acetylene and hydrogen remains unchanged upon illumination, suggesting that molecular surface coverage is not changed by light. By analyzing the inhomogeneity of the laser-induced heating, we attribute these results to a partial photothermal effect combined with a photochemical/hot electron-driven mechanism. Our findings highlight the capabilities of a new experiment automation tool; explore the photocatalytic mechanism for an industrially relevant reaction; and identify systematic sources of error in canonical photocatalysis experimental procedures.

  View details for DOI 10.1021/acs.jpca.5c02883

  View details for Web of Science ID 001520256300001

  View details for PubMedID 40583445

• Increasing the Structural Chirality of Metal Nanocrystals Created by Circularly Polarized Light via Surface Ligand Engineering. Small (Weinheim an der Bergstrasse, Germany) Qiao, T., Bordoloi, P., Ashworth, A. E., Miyashita, T., Mirmohammadi, S. S., Dionne, J. A., Tang, M. L. 2025: e2502440

  Abstract

  Plasmon-mediated synthesis enables isotropic metal nanocrystal growth with linearly polarized light. This limits the effect of the polarization of incident light during synthesis, and thusrestricts the structural chirality of nanocrystals produced with circularly polarized light (CPL). This study here demonstrates that surface engineering of initial achiral silver nanorods (AgNRs) can enhance the structural chirality of the resulting nanostructures produced with CPL. Specifically, the surface ligand hexadecyltrimethylammonium bromide (CTAB) stabilizes the lateral (100) facet-terminated sides of achiral AgNRs and inhibits lateral growth. This surface engineering with achiral ligands results in increased dissymmetry of the nanostructures during the early stages of photo-growth and leads to the formation of "hook" structures, where silver preferentially deposits near the tips of the nanorods. Upon further CPL illumination, these "hook" structures exhibit a significantly larger dissymmetry in the local electric field enhancement distribution compared to the initial achiral AgNRs. This highly dissymmetric electric field enhancement profile influences subsequent growth, resulting in AgNRs with enhanced structural chirality. Notably, the optical dissymmetry of these chiral nanostructures with g-factor 0.05 is an order of magnitude greater than that reported in previous studies conducted under similar chemical conditions but without surface engineering.

  View details for DOI 10.1002/smll.202502440

  View details for PubMedID 40528545

• Photons continue to surprise: a conversation with Harry Atwater ADVANCED PHOTONICS Dionne, J. 2025; 7 (3)

  View details for DOI 10.1117/1.AP.7.3.030501

  View details for Web of Science ID 001522275500015

• Upconverting microgauges reveal intraluminal force dynamics in vivo Casar, J. R., Goodman, M. B., Dionne, J. A., Mclellan, C. A., Shi, C., Gaerlan, M., Stiber, A. CELL PRESS. 2025

  View details for Web of Science ID 001510145400164

• Bacterial Wastewater-Based Epidemiology Using Surface-Enhanced Raman Spectroscopy and Machine Learning. Nano letters Herndon, L. K., Zhang, Y., Safir, F., Ogunlade, B., Balch, H. B., Boehm, A. B., Dionne, J. A. 2025

  Abstract

  Although wastewater-based epidemiology has been used extensively for the surveillance of viral diseases, it has not been used to a similar extent for bacterial diseases. This is in part owing to difficulties in distinguishing pathogenic from nonpathogenic bacteria using PCR methods. Here, we show that surface-enhanced Raman spectroscopy (SERS) can be a scalable, label-free method for the detection of bacteria in wastewater. We enhance Raman signal from bacteria in wastewater using plasmonic gold nanorods (AuNRs) that electrostatically bind to the bacterial surface and confirm this binding using cryoelectron microscopy. We spike four clinically relevant bacterial species and AuNRs into filtered wastewater, varying the AuNR concentration to maximize the signal. We then collect 540 spectra from each species at 109 cells/mL and train a machine learning model to identify them with more than 87% accuracy. We also demonstrate an environmentally realistic limit of detection of 104 cells/mL. These results are a key step toward a SERS platform for bacterial WBE.

  View details for DOI 10.1021/acs.nanolett.4c03703

  View details for PubMedID 39818848

• Upconverting microgauges reveal intraluminal force dynamics in vivo. Nature Casar, J. R., McLellan, C. A., Shi, C., Stiber, A., Lay, A., Siefe, C., Parakh, A., Gaerlan, M., Gu, X. W., Goodman, M. B., Dionne, J. A. 2025; 637 (8044): 76-83

  Abstract

  The forces generated by action potentials in muscle cells shuttle blood, food and waste products throughout the luminal structures of the body. Although non-invasive electrophysiological techniques exist1-3, most mechanosensors cannot access luminal structures non-invasively4-6. Here we introduce non-toxic ingestible mechanosensors to enable the quantitative study of luminal forces and apply them to study feeding in living Caenorhabditis elegans roundworms. These optical 'microgauges' comprise upconverting NaY0.8Yb0.18Er0.02F4@NaYF4 nanoparticles embedded in polystyrene microspheres. Combining optical microscopy and atomic force microscopy to study microgauges in vitro, we show that force evokes a linear and hysteresis-free change in the ratio of emitted red to green light. With fluorescence imaging and non-invasive electrophysiology, we show that adult C. elegans generate bite forces during feeding on the order of 10 µN and that the temporal pattern of force generation is aligned with muscle activity in the feeding organ. Moreover, the bite force we measure corresponds to Hertzian contact stresses in the pressure range used to lyse the bacterial food of the worm7,8. Microgauges have the potential to enable quantitative studies that investigate how neuromuscular stresses are affected by ageing, genetic mutations and drug treatments in this organ and other luminal organs.

  View details for DOI 10.1038/s41586-024-08331-x

  View details for PubMedID 39743609

  View details for PubMedCentralID 3372093

• High-throughput antibody screening with high-quality factor nanophotonics and bioprinting. ArXiv Abdollahramezani, S., Omo-Lamai, D., Bosman, G., Hemmatyar, O., Dagli, S., Dolia, V., Chang, K., Güsken, N. A., Delgado, H. C., Boons, G. J., Brongersma, M. L., Safir, F., Khuri-Yakub, B. T., Moradifar, P., Dionne, J. 2024

  Abstract

  Empirical investigation of the quintillion-scale, functionally diverse antibody repertoires that can be generated synthetically or naturally is critical for identifying potential biotherapeutic leads, yet remains burdensome. We present high-throughput nanophotonics- and bioprinter-enabled screening (HT-NaBS), a multiplexed assay for large-scale, sample-efficient, and rapid characterization of antibody libraries. Our platform is built upon independently addressable pixelated nanoantennas exhibiting wavelength-scale mode volumes, high-quality factors (high-Q) exceeding 5000, and pattern densities exceeding one million sensors per square centimeter. Our custom-built acoustic bioprinter enables individual sensor functionalization via the deposition of picoliter droplets from a library of capture antigens at rates up to 25,000 droplets per second. We detect subtle differentiation in the target binding signature through spatially-resolved spectral imaging of hundreds of resonators simultaneously, elucidating antigen-antibody binding kinetic rates, affinity constant, and specificity. We demonstrate HT-NaBS on a panel of antibodies targeting SARS-CoV-2, Influenza A, and Influenza B antigens, with a sub-picomolar limit of detection within 30 minutes. Furthermore, through epitope binning analysis, we demonstrate the competence and diversity of a library of native antibodies targeting functional epitopes on a priority pathogen (H5N1 bird flu) and on glycosylated therapeutic Cetuximab antibodies against epidermal growth factor receptor. With a roadmap to image tens of thousands of sensors simultaneously, this high-throughput, resource-efficient, and label-free platform can rapidly screen for high-affinity and broad epitope coverage, accelerating biotherapeutic discovery and de novo protein design.

  View details for PubMedID 39650601

  View details for PubMedCentralID PMC11623700

• Heart cockle shells transmit sunlight to photosymbiotic algae using bundled fiber optic cables and condensing lenses. Nature communications McCoy, D. E., Burns, D. H., Klopfer, E., Herndon, L. K., Ogunlade, B., Dionne, J. A., Johnsen, S. 2024; 15 (1): 9445

  Abstract

  Many animals convergently evolved photosynthetic symbioses. In bivalves, giant clams (Cardiidae: Tridacninae) gape open to irradiate their symbionts, but heart cockles (Cardiidae: Fraginae) stay closed because sunlight passes through transparent windows in their shells. Here, we show that heart cockles (Corculum cardissa and spp.) use biophotonic adaptations to transmit sunlight for photosynthesis. Heart cockles transmit 11-62% of photosynthetically active radiation (mean = 31%) but only 5-28% of potentially harmful UV radiation (mean = 14%) to their symbionts. Beneath each window, microlenses condense light to penetrate more deeply into the symbiont-rich tissue. Within each window, aragonite forms narrow fibrous prisms perpendicular to the surface. These bundled "fiber optic cables" project images through the shell with a resolution of >100 lines/mm. Parameter sweeps show that the aragonite fibers' size (~1 µm diameter), morphology (long fibers rather than plates), and orientation (along the optical c-axis) transmit more light than many other possible designs. Heart cockle shell windows are thus: (i) the first instance of fiber optic cable bundles in an organism to our knowledge; (ii) a second evolution, with epidermal cells in angiosperm plants, of condensing lenses for photosynthesis; and (iii) a photonic system that efficiently transmits useful light while protecting photosymbionts from UV radiation.

  View details for DOI 10.1038/s41467-024-53110-x

  View details for PubMedID 39562764

  View details for PubMedCentralID PMC11576985

• Author Correction: Highly confined epsilon-near-zero and surface phonon polaritons in SrTiO3membranes. Nature communications Xu, R., Crassee, I., Bechtel, H. A., Zhou, Y., Bercher, A., Korosec, L., Rischau, C. W., Teyssier, J., Crust, K. J., Lee, Y., Gilbert Corder, S. N., Li, J., Dionne, J. A., Hwang, H. Y., Kuzmenko, A. B., Liu, Y. 2024; 15 (1): 8545

  View details for DOI 10.1038/s41467-024-52983-2

  View details for PubMedID 39358377

• <i>Nano Letters</i> Seed Grants, Take Two NANO LETTERS Odom, T. W., Besley, E., Colvin, V., Dionne, J. A., Herrmann, C., Nie, G., Prieto, A. L., van der Zande, A. M., Wang, H. 2024

  View details for DOI 10.1021/acs.nanolett.4c03901

  View details for Web of Science ID 001317070200001

  View details for PubMedID 39297535

• p53 Regulates Nuclear Architecture to Reduce Carcinogen Sensitivity and Mutagenic Potential. bioRxiv : the preprint server for biology King, D. A., McCoy, D. E., Perdyan, A., Mieczkowski, J., Douki, T., Dionne, J. A., Herrera, R. E., Morrison, A. J. 2024

  Abstract

  The p53 tumor suppressor is an indispensable regulator of DNA damage responses that accelerates carcinogenesis when mutated. In this report, we uncover a new mechanism by which p53 maintains genomic integrity in the absence of canonical DNA damage response activation. Specifically, loss of p53 dramatically alters chromatin structure at the nuclear periphery, allowing increased transmission of an environmental carcinogen, ultraviolet (UV) radiation, into the nucleus. Genome-wide mapping of UV-induced DNA lesions in p53-deficient primary cells reveals elevated lesion abundance in regions corresponding to locations of high mutation burden in malignant melanomas. These findings uncover a novel role of p53 in the suppression of mutations that contribute to cancer and highlight the critical influence of nuclear architecture in regulating sensitivity to carcinogens.One-Sentence Summary: The p53 tumor suppressor reduces carcinogen sensitivity and mutagenic potential by maintaining nuclear architecture.

  View details for DOI 10.1101/2024.09.14.613067

  View details for PubMedID 39345432

• Targeted materials discovery using Bayesian algorithm execution NPJ COMPUTATIONAL MATERIALS Chitturi, S. R., Ramdas, A., Wu, Y., Rohr, B., Ermon, S., Dionne, J., da Jornada, F. H., Dunne, M., Tassone, C., Neiswanger, W., Ratner, D. 2024; 10 (1)

  View details for DOI 10.1038/s41524-024-01326-2

  View details for Web of Science ID 001271730700002

• The role of the plasmon in interfacial charge transfer. Science advances Ostovar, B., Lee, S. A., Mehmood, A., Farrell, K., Searles, E. K., Bourgeois, B., Chiang, W. Y., Misiura, A., Gross, N., Al-Zubeidi, A., Dionne, J. A., Landes, C. F., Zanni, M., Levine, B. G., Link, S. 2024; 10 (27): eadp3353

  Abstract

  The lack of a detailed mechanistic understanding for plasmon-mediated charge transfer at metal-semiconductor interfaces severely limits the design of efficient photovoltaic and photocatalytic devices. A major remaining question is the relative contribution from indirect transfer of hot electrons generated by plasmon decay in the metal to the semiconductor compared to direct metal-to-semiconductor interfacial charge transfer. Here, we demonstrate an overall electron transfer efficiency of 44 ± 3% from gold nanorods to titanium oxide shells when excited on resonance. We prove that half of it originates from direct interfacial charge transfer mediated specifically by exciting the plasmon. We are able to distinguish between direct and indirect pathways through multimodal frequency-resolved approach measuring the homogeneous plasmon linewidth by single-particle scattering spectroscopy and time-resolved transient absorption spectroscopy with variable pump wavelengths. Our results signify that the direct plasmon-induced charge transfer pathway is a promising way to improve hot carrier extraction efficiency by circumventing metal intrinsic decay that results mainly in nonspecific heating.

  View details for DOI 10.1126/sciadv.adp3353

  View details for PubMedID 38968358

• Very-large-scale integrated high quality factor nanoantenna pixels. Nature nanotechnology Dolia, V., Balch, H. B., Dagli, S., Abdollahramezani, S., Carr Delgado, H., Moradifar, P., Chang, K., Stiber, A., Safir, F., Lawrence, M., Hu, J., Dionne, J. A. 2024

  Abstract

  Metasurfaces precisely control the amplitude, polarization and phase of light, with applications spanning imaging, sensing, modulation and computing. Three crucial performance metrics of metasurfaces and their constituent resonators are the quality factor (Q factor), mode volume (Vm) and ability to control far-field radiation. Often, resonators face a trade-off between these parameters: a reduction in Vm leads to an equivalent reduction in Q, albeit with more control over radiation. Here we demonstrate that this perceived compromise is not inevitable: high quality factor, subwavelength Vm and controlled dipole-like radiation can be achieved simultaneously. We design high quality factor, very-large-scale-integrated silicon nanoantenna pixels (VINPix) that combine guided mode resonance waveguides with photonic crystal cavities. With optimized nanoantennas, we achieve Q factors exceeding 1,500 with Vm less than 0.1 ( λ / n air ) 3 . Each nanoantenna is individually addressable by free-space light and exhibits dipole-like scattering to the far-field. Resonator densities exceeding a million nanoantennas per cm2 can be achieved. As a proof-of-concept application, we show spectrometer-free, spatially localized, refractive-index sensing, and fabrication of an 8 mm × 8 mm VINPix array. Our platform provides a foundation for compact, densely multiplexed devices such as spatial light modulators, computational spectrometers and in situ environmental sensors.

  View details for DOI 10.1038/s41565-024-01697-z

  View details for PubMedID 38961248

  View details for PubMedCentralID 10971570

• From Genotype to Phenotype: Raman Spectroscopy and Machine Learning for Label-Free Single-Cell Analysis. ACS nano Zhang, Y., Chang, K., Ogunlade, B., Herndon, L., Tadesse, L. F., Kirane, A. R., Dionne, J. A. 2024

  Abstract

  Raman spectroscopy has made significant progress in biosensing and clinical research. Here, we describe how surface-enhanced Raman spectroscopy (SERS) assisted with machine learning (ML) can expand its capabilities to enable interpretable insights into the transcriptome, proteome, and metabolome at the single-cell level. We first review how advances in nanophotonics-including plasmonics, metamaterials, and metasurfaces-enhance Raman scattering for rapid, strong label-free spectroscopy. We then discuss ML approaches for precise and interpretable spectral analysis, including neural networks, perturbation and gradient algorithms, and transfer learning. We provide illustrative examples of single-cell Raman phenotyping using nanophotonics and ML, including bacterial antibiotic susceptibility predictions, stem cell expression profiles, cancer diagnostics, and immunotherapy efficacy and toxicity predictions. Lastly, we discuss exciting prospects for the future of single-cell Raman spectroscopy, including Raman instrumentation, self-driving laboratories, Raman data banks, and machine learning for uncovering biological insights.

  View details for DOI 10.1021/acsnano.4c04282

  View details for PubMedID 38950145

• Rapid, antibiotic incubation-free determination of tuberculosis drug resistance using machine learning and Raman spectroscopy. Proceedings of the National Academy of Sciences of the United States of America Ogunlade, B., Tadesse, L. F., Li, H., Vu, N., Banaei, N., Barczak, A. K., Saleh, A. A., Prakash, M., Dionne, J. A. 2024; 121 (25): e2315670121

  Abstract

  Tuberculosis (TB) is the world's deadliest infectious disease, with over 1.5 million deaths and 10 million new cases reported anually. The causative organism Mycobacterium tuberculosis (Mtb) can take nearly 40 d to culture, a required step to determine the pathogen's antibiotic susceptibility. Both rapid identification and rapid antibiotic susceptibility testing of Mtb are essential for effective patient treatment and combating antimicrobial resistance. Here, we demonstrate a rapid, culture-free, and antibiotic incubation-free drug susceptibility test for TB using Raman spectroscopy and machine learning. We collect few-to-single-cell Raman spectra from over 25,000 cells of the Mtb complex strain Bacillus Calmette-Guérin (BCG) resistant to one of the four mainstay anti-TB drugs, isoniazid, rifampicin, moxifloxacin, and amikacin, as well as a pan-susceptible wildtype strain. By training a neural network on this data, we classify the antibiotic resistance profile of each strain, both on dried samples and on patient sputum samples. On dried samples, we achieve >98% resistant versus susceptible classification accuracy across all five BCG strains. In patient sputum samples, we achieve ~79% average classification accuracy. We develop a feature recognition algorithm in order to verify that our machine learning model is using biologically relevant spectral features to assess the resistance profiles of our mycobacterial strains. Finally, we demonstrate how this approach can be deployed in resource-limited settings by developing a low-cost, portable Raman microscope that costs <$5,000. We show how this instrument and our machine learning model enable combined microscopy and spectroscopy for accurate few-to-single-cell drug susceptibility testing of BCG.

  View details for DOI 10.1073/pnas.2315670121

  View details for PubMedID 38861604

• Highly confined epsilon-near-zero and surface phonon polaritons in SrTiO3 membranes. Nature communications Xu, R., Crassee, I., Bechtel, H. A., Zhou, Y., Bercher, A., Korosec, L., Rischau, C. W., Teyssier, J., Crust, K. J., Lee, Y., Gilbert Corder, S. N., Li, J., Dionne, J. A., Hwang, H. Y., Kuzmenko, A. B., Liu, Y. 2024; 15 (1): 4743

  Abstract

  Recent theoretical studies have suggested that transition metal perovskite oxide membranes can enable surface phonon polaritons in the infrared range with low loss and much stronger subwavelength confinement than bulk crystals. Such modes, however, have not been experimentally observed so far. Here, using a combination of far-field Fourier-transform infrared (FTIR) spectroscopy and near-field synchrotron infrared nanospectroscopy (SINS) imaging, we study the phonon polaritons in a 100 nm thick freestanding crystalline membrane of SrTiO3 transferred on metallic and dielectric substrates. We observe a symmetric-antisymmetric mode splitting giving rise to epsilon-near-zero and Berreman modes as well as highly confined (by a factor of 10) propagating phonon polaritons, both of which result from the deep-subwavelength thickness of the membranes. Theoretical modeling based on the analytical finite-dipole model and numerical finite-difference methods fully corroborate the experimental results. Our work reveals the potential of oxide membranes as a promising platform for infrared photonics and polaritonics.

  View details for DOI 10.1038/s41467-024-47917-x

  View details for PubMedID 38834672

  View details for PubMedCentralID 9799068

• Spectroscopy in Nanoscopic Cavities: Models and Recent Experiments. Annual review of physical chemistry Bourgeois, M. R., Pan, F., Anyanwu, C. P., Nixon, A. G., Beutler, E. K., Dionne, J. A., Goldsmith, R. H., Masiello, D. J. 2024; 75 (1): 509-534

  Abstract

  The ability of nanophotonic cavities to confine and store light to nanoscale dimensions has important implications for enhancing molecular, excitonic, phononic, and plasmonic optical responses. Spectroscopic signatures of processes that are ordinarily exceedingly weak such as pure absorption and Raman scattering have been brought to the single-particle limit of detection, while new emergent polaritonic states of optical matter have been realized through coupling material and photonic cavity degrees of freedom across a wide range of experimentally accessible interaction strengths. In this review, we discuss both optical and electron beam spectroscopies of cavity-coupled material systems in weak, strong, and ultrastrong coupling regimes, providing a theoretical basis for understanding the physics inherent to each while highlighting recent experimental advances and exciting future directions.

  View details for DOI 10.1146/annurev-physchem-083122-125525

  View details for PubMedID 38941525

• MicrobioRaman: an open-access web repository for microbiological Raman spectroscopy data. Nature microbiology Lee, K. S., Landry, Z., Athar, A., Alcolombri, U., Pramoj Na Ayutthaya, P., Berry, D., de Bettignies, P., Cheng, J. X., Csucs, G., Cui, L., Deckert, V., Dieing, T., Dionne, J., Doskocil, O., D'Souza, G., García-Timermans, C., Gierlinger, N., Goda, K., Hatzenpichler, R., Henshaw, R. J., Huang, W. E., Iermak, I., Ivleva, N. P., Kneipp, J., Kubryk, P., Küsel, K., Lee, T. K., Lee, S. S., Ma, B., Martínez-Pérez, C., Matousek, P., Meckenstock, R. U., Min, W., Mojzeš, P., Müller, O., Kumar, N., Nielsen, P. H., Notingher, I., Palatinszky, M., Pereira, F. C., Pezzotti, G., Pilat, Z., Plesinger, F., Popp, J., Probst, A. J., Riva, A., Saleh, A. A., Samek, O., Sapers, H. M., Schubert, O. T., Stubbusch, A. K., Tadesse, L. F., Taylor, G. T., Wagner, M., Wang, J., Yin, H., Yue, Y., Zenobi, R., Zini, J., Sarkans, U., Stocker, R. 2024

  View details for DOI 10.1038/s41564-024-01656-3

  View details for PubMedID 38714759

  View details for PubMedCentralID 9723680

• Toward "super-scintillation" with nanomaterials and nanophotonics. Nanophotonics Carr Delgado, H., Moradifar, P., Chinn, G., Levin, C. S., Dionne, J. A. 2024; 13 (11): 1953-1962

  Abstract

  Following the discovery of X-rays, scintillators are commonly used as high-energy radiation sensors in diagnostic medical imaging, high-energy physics, astrophysics, environmental radiation monitoring, and security inspections. Conventional scintillators face intrinsic limitations including a low extraction efficiency of scintillated light and a low emission rate, leading to efficiencies that are less than 10 % for commercial scintillators. Overcoming these limitations will require new materials including scintillating nanomaterials ("nanoscintillators"), as well as new photonic approaches that increase the efficiency of the scintillation process, increase the emission rate of materials, and control the directivity of the scintillated light. In this perspective, we describe emerging nanoscintillating materials and three nanophotonic platforms: (i) plasmonic nanoresonators, (ii) photonic crystals, and (iii) high-Q metasurfaces that could enable high performance scintillators. We further discuss how a combination of nanoscintillators and photonic structures can yield a "super scintillator" enabling ultimate spatio-temporal resolution while enabling a significant boost in the extracted scintillation emission.

  View details for DOI 10.1515/nanoph-2023-0946

  View details for PubMedID 38745841

  View details for PubMedCentralID PMC11090085

• Toward "super-scintillation" with nanomaterials and nanophotonics NANOPHOTONICS Delgado, H., Moradifar, P., Chinn, G., Levin, C. S., Dionne, J. A. 2024

  View details for DOI 10.1515/nanoph-2023-0946

  View details for Web of Science ID 001201678800001

• Solution-phase sample-averaged single-particle spectroscopy of quantum emitters with femtosecond resolution. Nature materials Shi, J., Shen, Y., Pan, F., Sun, W., Mangu, A., Shi, C., McKeown-Green, A., Moradifar, P., Bawendi, M. G., Moerner, W. E., Dionne, J. A., Liu, F., Lindenberg, A. M. 2024

  Abstract

  The development of many quantum optical technologies depends on the availability of single quantum emitters with near-perfect coherence. Systematic improvement is limited by a lack of understanding of the microscopic energy flow at the single-emitter level and ultrafast timescales. Here we utilize a combination of fluorescence correlation spectroscopy and ultrafast spectroscopy to capture the sample-averaged dynamics of defects with single-particle sensitivity. We employ this approach to study heterogeneous emitters in two-dimensional hexagonal boron nitride. From milliseconds to nanoseconds, the translational, shelving, rotational and antibunching features are disentangled in time, which quantifies the normalized two-photon emission quantum yield. Leveraging the femtosecond resolution of this technique, we visualize electron-phonon coupling and discover the acceleration of polaronic formation on multi-electron excitation. Corroborated with theory, this translates to the photon fidelity characterization of cascaded emission efficiency and decoherence time. Our work provides a framework for ultrafast spectroscopy in heterogeneous emitters, opening new avenues of extreme-scale characterization for quantum applications.

  View details for DOI 10.1038/s41563-024-01855-7

  View details for PubMedID 38589542

  View details for PubMedCentralID 5615041

• Unraveling sources of emission heterogeneity in Silicon Vacancy color centers with cryo-cathodoluminescence microscopy. Proceedings of the National Academy of Sciences of the United States of America Angell, D. K., Li, S., Utzat, H., Thurston, M. L., Liu, Y., Dahl, J., Carlson, R., Shen, Z. X., Melosh, N., Sinclair, R., Dionne, J. A. 2024; 121 (14): e2308247121

  Abstract

  Diamond color centers have proven to be versatile quantum emitters and exquisite sensors of stress, temperature, electric and magnetic fields, and biochemical processes. Among color centers, the silicon-vacancy (SiV[Formula: see text]) defect exhibits high brightness, minimal phonon coupling, narrow optical linewidths, and high degrees of photon indistinguishability. Yet the creation of reliable and scalable SiV[Formula: see text]-based color centers has been hampered by heterogeneous emission, theorized to originate from surface imperfections, crystal lattice strain, defect symmetry, or other lattice impurities. Here, we advance high-resolution cryo-electron microscopy combined with cathodoluminescence spectroscopy and 4D scanning transmission electron microscopy (STEM) to elucidate the structural sources of heterogeneity in SiV[Formula: see text] emission from nanodiamond with sub-nanometer-scale resolution. Our diamond nanoparticles are grown directly on TEM membranes from molecular-level seedings, representing the natural formation conditions of color centers in diamond. We show that individual subcrystallites within a single nanodiamond exhibit distinct zero-phonon line (ZPL) energies and differences in brightness that can vary by 0.1 meV in energy and over 70% in brightness. These changes are correlated with the atomic-scale lattice structure. We find that ZPL blue-shifts result from tensile strain, while ZPL red shifts are due to compressive strain. We also find that distinct crystallites host distinct densities of SiV[Formula: see text] emitters and that grain boundaries impact SiV[Formula: see text] emission significantly. Finally, we interrogate nanodiamonds as small as 40 nm in diameter and show that these diamonds exhibit no spatial change to their ZPL energy. Our work provides a foundation for atomic-scale structure-emission correlation, e.g., of single atomic defects in a range of quantum and two-dimensional materials.

  View details for DOI 10.1073/pnas.2308247121

  View details for PubMedID 38551833

• Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation ACS APPLIED NANO MATERIALS McKeown-Green, A. S., Zeng, H. J., Saunders, A. P., Li, J., Shi, J., Shen, Y., Pan, F., Hu, J., Dionne, J. A., Heinz, T. F., Wu, S. M., Zheng, F., Liu, F. 2024

  View details for DOI 10.1021/acsanm.4c00412

  View details for Web of Science ID 001184723800001

• Tuning the Chiral Growth of Plasmonic Bipyramids via the Wavelength and Polarization of Light. Nano letters Qiao, T., Bordoloi, P., Miyashita, T., Dionne, J. A., Tang, M. L. 2024

  Abstract

  Circularly polarized light (CPL) is a versatile tool to prepare chiral nanostructures, but the mechanism for inducing enantioselectivity is not well understood. This work shows that the energy and polarization of visible photons can initiate photodeposition at different sites on plasmonic nanocrystals. Here, CPL on achiral gold bipyramids (AuBPs) creates hot holes that oxidatively deposit PbO2 asymmetrically. We show for the first time that the location of PbO2 photodeposition and hence optical dissymmetry depends on the CPL wavelength. Specifically, 488 and 532 nm CPL induce PbO2 growth in the middle of AuBPs, whereas 660 nm CPL induces PbO2 growth at the tips. Our observations show that wavelength-dependent plasmonic field distributions are more important than surface lightning rod effects in localizing plasmon-mediated photochemistry. The largest optical dissymmetry occurs at excitation wavelengths between the transverse and longitudinal resonances of the AuBPs because higher-order modes are required to induce chiral electric fields.

  View details for DOI 10.1021/acs.nanolett.3c04862

  View details for PubMedID 38357869

• Quantitative gas-phase transmission electron microscopy: Where are we now and what comes next? MRS BULLETIN Jinschek, J. R., Helveg, S., Allard, L. F., Dionne, J. A., Zhu, Y., Crozier, P. A. 2024

  View details for DOI 10.1557/s43577-023-00648-8

  View details for Web of Science ID 001158126600001

• Advancing precision cancer immunotherapy drug development, administration, and response prediction with AI-enabled Raman spectroscopy. Frontiers in immunology Chadokiya, J., Chang, K., Sharma, S., Hu, J., Lill, J. R., Dionne, J., Kirane, A. 2024; 15: 1520860

  Abstract

  Molecular characterization of tumors is essential to identify predictive biomarkers that inform treatment decisions and improve precision immunotherapy development and administration. However, challenges such as the heterogeneity of tumors and patient responses, limited efficacy of current biomarkers, and the predominant reliance on single-omics data, have hindered advances in accurately predicting treatment outcomes. Standard therapy generally applies a "one size fits all" approach, which not only provides ineffective or limited responses, but also an increased risk of off-target toxicities and acceleration of resistance mechanisms or adverse effects. As the development of emerging multi- and spatial-omics platforms continues to evolve, an effective tumor assessment platform providing utility in a clinical setting should i) enable high-throughput and robust screening in a variety of biological matrices, ii) provide in-depth information resolved with single to subcellular precision, and iii) improve accessibility in economical point-of-care settings. In this perspective, we explore the application of label-free Raman spectroscopy as a tumor profiling tool for precision immunotherapy. We examine how Raman spectroscopy's non-invasive, label-free approach can deepen our understanding of intricate inter- and intra-cellular interactions within the tumor-immune microenvironment. Furthermore, we discuss the analytical advances in Raman spectroscopy, highlighting its evolution to be utilized as a single "Raman-omics" approach. Lastly, we highlight the translational potential of Raman for its integration in clinical practice for safe and precise patient-centric immunotherapy.

  View details for DOI 10.3389/fimmu.2024.1520860

  View details for PubMedID 39850874

  View details for PubMedCentralID PMC11753970

• Nanoscale and ultrafast <i>in situ</i> techniques to probe plasmon photocatalysis CHEMICAL PHYSICS REVIEWS Carlin, C. C., Dai, A. X., Al-Zubeidi, A., Simmerman, E. M., Oh, H., Gross, N., Lee, S. A., Link, S., Landes, C. F., da Jornada, F. H., Dionne, J. A. 2023; 4 (4)

  View details for DOI 10.1063/5.0163354

  View details for Web of Science ID 001112242700001

• Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy. Chemical reviews Moradifar, P., Liu, Y., Shi, J., Siukola Thurston, M. L., Utzat, H., van Driel, T. B., Lindenberg, A. M., Dionne, J. A. 2023

  Abstract

  Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material's detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure-function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials' intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.

  View details for DOI 10.1021/acs.chemrev.2c00917

  View details for PubMedID 37979189

• High-Throughput Screening of Optical Properties of Glass-Supported Plasmonic Nanoparticles Fabricated by Polymer Pen Lithography JOURNAL OF PHYSICAL CHEMISTRY C Gross, N., Wang, W., Brasel, S., Searles, E. K., Bourgeois, B., Dionne, J. A., Landes, C. F., Link, S. 2023; 127 (39): 19607-19619

  View details for DOI 10.1021/acs.jpcc.3c04521

  View details for Web of Science ID 001075619100001

• The carotenoid redshift: Physical basis and implications for visual signaling. Ecology and evolution McCoy, D. E., Shultz, A. J., Dall, J. E., Dionne, J. A., Johnsen, S. 2023; 13 (9): e10408

  Abstract

  Carotenoid pigments are the basis for much red, orange, and yellow coloration in nature and central to visual signaling. However, as pigment concentration increases, carotenoid signals not only darken and become more saturated but they also redshift; for example, orange pigments can look red at higher concentration. This occurs because light experiences exponential attenuation, and carotenoid-based signals have spectrally asymmetric reflectance in the visible range. Adding pigment disproportionately affects the high-absorbance regions of the reflectance spectra, which redshifts the perceived hue. This carotenoid redshift is substantial and perceivable by animal observers. In addition, beyond pigment concentration, anything that increases the path length of light through pigment causes this redshift (including optical nano- and microstructures). For example, male Ramphocelus tanagers appear redder than females, despite the same population and concentration of carotenoids, due to microstructures that enhance light-pigment interaction. This mechanism of carotenoid redshift has sensory and evolutionary consequences for honest signaling in that structures that redshift carotenoid ornaments may decrease signal honesty. More generally, nearly all colorful signals vary in hue, saturation, and brightness as light-pigment interactions change, due to spectrally asymmetrical reflectance within the visible range of the relevant species. Therefore, the three attributes of color need to be considered together in studies of honest visual signaling.

  View details for DOI 10.1002/ece3.10408

  View details for PubMedID 37693937

  View details for PubMedCentralID PMC10485323

• Progress and Prospects in Optical Ultrafast Microscopy in the Visible Spectral Region: Transient Absorption and Two-Dimensional Microscopy. The journal of physical chemistry. C, Nanomaterials and interfaces Gross, N., Kuhs, C. T., Ostovar, B., Chiang, W. Y., Wilson, K. S., Volek, T. S., Faitz, Z. M., Carlin, C. C., Dionne, J. A., Zanni, M. T., Gruebele, M., Roberts, S. T., Link, S., Landes, C. F. 2023; 127 (30): 14557-14586

  Abstract

  Ultrafast optical microscopy, generally employed by incorporating ultrafast laser pulses into microscopes, can provide spatially resolved mechanistic insight into scientific problems ranging from hot carrier dynamics to biological imaging. This Review discusses the progress in different ultrafast microscopy techniques, with a focus on transient absorption and two-dimensional microscopy. We review the underlying principles of these techniques and discuss their respective advantages and applicability to different scientific questions. We also examine in detail how instrument parameters such as sensitivity, laser power, and temporal and spatial resolution must be addressed. Finally, we comment on future developments and emerging opportunities in the field of ultrafast microscopy.

  View details for DOI 10.1021/acs.jpcc.3c02091

  View details for PubMedID 37554548

  View details for PubMedCentralID PMC10406104

• Rapid genetic screening with high quality factor metasurfaces. Nature communications Hu, J., Safir, F., Chang, K., Dagli, S., Balch, H. B., Abendroth, J. M., Dixon, J., Moradifar, P., Dolia, V., Sahoo, M. K., Pinsky, B. A., Jeffrey, S. S., Lawrence, M., Dionne, J. A. 2023; 14 (1): 4486

  Abstract

  Genetic analysis methods are foundational to advancing personalized medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) rely on sample amplification and can suffer from inhibition. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with nucleic acid fragments. Each high-Q nanoantenna exhibits average resonant quality factors of 2,200 in physiological buffer. We quantitatively detect two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), with high-specificity via DNA hybridization. We also demonstrate femtomolar sensitivity in buffer and nanomolar sensitivity in spiked nasopharyngeal eluates within 5 minutes. Nanoantennas are patterned at densities of 160,000 devices per cm2, enabling future work on highly-multiplexed detection. Combined with advances in complex sample processing, our work provides a foundation for rapid, compact, and amplification-free molecular assays.

  View details for DOI 10.1038/s41467-023-39721-w

  View details for PubMedID 37495593

  View details for PubMedCentralID PMC10372074

• Progress and Prospects in Optical Ultrafast Microscopy in the Visible Spectral Region: Transient Absorption and Two-Dimensional Microscopy JOURNAL OF PHYSICAL CHEMISTRY C Gross, N., Kuhs, C. T., Ostovar, B., Chiang, W., Wilson, K. S., Volek, T. S., Faitz, Z. M., Carlin, C. C., Dionne, J. A., Zanni, M. T., Gruebele, M., Roberts, S. T., Link, S., Landes, C. F. 2023

  View details for DOI 10.1021/acs.jpcc.3c02091

  View details for Web of Science ID 001034961500001

• Linking Atomic and Reactor Scale Plasmon Photocatalysis in Acetylene Hydrogenation with Optically Coupled ETEM. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada Bourgeois, B., Carlin, C., Angell, D., Swearer, D., Cheng, W. H., Dai, A., Yuan, L., Dionne, J. 2023; 29 (Supplement_1): 1298-1299

  View details for DOI 10.1093/micmic/ozad067.664

  View details for PubMedID 37613409

• Sustainable chemistry with plasmonic photocatalysts. Nanophotonics (Berlin, Germany) Yuan, L., Bourgeois, B. B., Carlin, C. C., da Jornada, F. H., Dionne, J. A. 2023; 12 (14): 2745-2762

  Abstract

  There is a pressing global need to increase the use of renewable energy sources and limit greenhouse gas emissions. Towards this goal, highly efficient and molecularly selective chemical processes that operate under mild conditions are critical. Plasmonic photocatalysis uses optically-resonant metallic nanoparticles and their resulting plasmonic, electronic, and phononic light-matter interactions to drive chemical reactions. The promise of simultaneous high-efficiency and product-selective reactions with plasmon photocatalysis provides a compelling opportunity to rethink how chemistry is achieved. Plasmonic nanoparticles serve as nanoscale 'antennas' that enable strong light-matter interactions, surpassing the light-harvesting capabilities one would expect purely from their size. Complex composite structures, combining engineered light harvesters with more chemically active components, are a focal point of current research endeavors. In this review, we provide an overview of recent advances in plasmonic catalysis. We start with a discussion of the relevant mechanisms in photochemical transformations and explain hot-carrier generation and distributions from several ubiquitous plasmonic antennae. Then we highlight three important types of catalytic processes for sustainable chemistry: ammonia synthesis, hydrogen production and CO2 reduction. To help elucidate the reaction mechanism, both state-of-art electromagnetic calculations and quantum mechanistic calculations are discussed. This review provides insights to better understand the mechanism of plasmonic photocatalysis with a variety of metallic and composite nanostructures toward designing and controlling improved platforms for green chemistry in the future.

  View details for DOI 10.1515/nanoph-2023-0149

  View details for PubMedID 39635497

  View details for PubMedCentralID PMC11501645

• Through thick and thin: how optical cavities control spin. Nanophotonics (Berlin, Germany) Dixon, J., Pan, F., Moradifar, P., Bordoloi, P., Dagli, S., Dionne, J. 2023; 12 (14): 2779-2788

  Abstract

  When light interacts with matter by means of scattering and absorption, we observe the resulting color. Light also probes the symmetry of matter and the result is encoded in its polarization. In the special case of circularly-polarized light, which is especially relevant in nonlinear optics, quantum photonics, and physical chemistry, a critical dimension of symmetry is along the longitudinal direction. We examine recent advances in controlling circularly-polarized light and reveal that the commonality in these advances is in judicious control of longitudinal symmetry. In particular, in the use of high quality-factor modes in dielectric metasurfaces, the finite thickness can be used to tune the modal profile. These symmetry considerations can be applied in multiplexed optical communication schemes, deterministic control of quantum emitters, and sensitive detection of the asymmetry of small molecules.

  View details for DOI 10.1515/nanoph-2023-0175

  View details for PubMedID 39635484

  View details for PubMedCentralID PMC11501721

• 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

• Predicting tuberculosis drug resistance with machine learning-assisted Raman spectroscopy. ArXiv Ogunlade, B., Tadesse, L. F., Li, H., Vu, N., Banaei, N., Barczak, A. K., Saleh, A. A., Prakash, M., Dionne, J. A. 2023

  Abstract

  Tuberculosis (TB) is the world's deadliest infectious disease, with 1.5 million annual deaths and half a million annual infections. Rapid TB diagnosis and antibiotic susceptibility testing (AST) are critical to improve patient treatment and to reduce the rise of new drug resistance. Here, we develop a rapid, label-free approach to identify Mycobacterium tuberculosis (Mtb) strains and antibiotic-resistant mutants. We collect over 20,000 single-cell Raman spectra from isogenic mycobacterial strains each resistant to one of the four mainstay anti-TB drugs (isoniazid, rifampicin, moxifloxacin and amikacin) and train a machine-learning model on these spectra. On dried TB samples, we achieve > 98% classification accuracy of the antibiotic resistance profile, without the need for antibiotic co-incubation; in dried patient sputum, we achieve average classification accuracies of ~ 79%. We also develop a low-cost, portable Raman microscope suitable for field-deployment of this method in TB-endemic regions.

  View details for DOI 10.3390/molecules24244516

  View details for PubMedID 37332564

  View details for PubMedCentralID PMC10274949

• Kinetics and mechanism of light-induced phase separation in a mixed-halide perovskite MATTER Peng, S., Wang, Y., Braun, M., Yin, Y., Meng, A. C., Tan, W., Saini, B., Severson, K., Marshall, A. F., Sytwu, K., Baniecki, J. D., Dionne, J., Cai, W., McIntyre, P. C. 2023; 6 (6): 2052-2065

  View details for DOI 10.1016/j.matt.2023.04.025

  View details for Web of Science ID 001043983600001

• Nanophotonics for a sustainable future PHYSICS TODAY Dionne, J. A., Dagli, S., Shalaev, V. M. 2023; 76 (6): 24-31

  View details for DOI 10.1063/PT.3.5254

  View details for Web of Science ID 001054531900010

• Sustainable chemistry with plasmonic photocatalysts NANOPHOTONICS Yuan, L., Bourgeois, B. B., Carlin, C. C., da Jornada, F. H., Dionne, J. A. 2023

  View details for DOI 10.1515/nanoph-2023-0149

  View details for Web of Science ID 000998563800001

• A thermally controlled high-Q metasurface lens APPLIED PHYSICS LETTERS Klopfer, E., Delgado, H., Dagli, S., Lawrence, M., Dionne, J. A. 2023; 122 (22)

  View details for DOI 10.1063/5.0152535

  View details for Web of Science ID 001000068400003

• Through thick and thin: how optical cavities control spin NANOPHOTONICS Dixon, J., Pan, F., Moradifar, P., Bordoloi, P., Dagli, S., Dionne, J. 2023

  View details for DOI 10.1515/nanoph-2023-0175

  View details for Web of Science ID 000982262200001

• LiH formation and its impact on Li batteries revealed by cryogenic electron microscopy. Science advances Vilá, R. A., Boyle, D. T., Dai, A., Zhang, W., Sayavong, P., Ye, Y., Yang, Y., Dionne, J. A., Cui, Y. 2023; 9 (12): eadf3609

  Abstract

  Little is known about how evolved hydrogen affects the cycling of Li batteries. Hypotheses include the formation of LiH in the solid-electrolyte interphase (SEI) and dendritic growth of LiH. Here, we discover that LiH formation in Li batteries likely follows a different pathway: Hydrogen evolved during cycling reacts to nucleate and grow LiH within already deposited Li metal, consuming active Li. We provide the evidence that LiH formed in Li batteries electrically isolates active Li from the current collector that degrades battery capacity. We detect the coexistence of Li metal and LiH also on graphite and silicon anodes, showing that LiH forms in most Li battery anode chemistries. Last, we find that LiH has its own SEI layer that is chemically and structurally distinct from the SEI on Li metal. Our results highlight the formation mechanism and chemical origins of LiH, providing critical insight into how to prevent its formation.

  View details for DOI 10.1126/sciadv.adf3609

  View details for PubMedID 36961896

• Combining Acoustic Bioprinting with AI-Assisted Raman Spectroscopy for High-Throughput Identification of Bacteria in Blood. Nano letters Safir, F., Vu, N., Tadesse, L. F., Firouzi, K., Banaei, N., Jeffrey, S. S., Saleh, A. A., Khuri-Yakub, B. P., Dionne, J. A. 2023

  Abstract

  Identifying pathogens in complex samples such as blood, urine, and wastewater is critical to detect infection and inform optimal treatment. Surface-enhanced Raman spectroscopy (SERS) and machine learning (ML) can distinguish among multiple pathogen species, but processing complex fluid samples to sensitively and specifically detect pathogens remains an outstanding challenge. Here, we develop an acoustic bioprinter to digitize samples into millions of droplets, each containing just a few cells, which are identified with SERS and ML. We demonstrate rapid printing of 2 pL droplets from solutions containing S. epidermidis, E. coli, and blood; when they are mixed with gold nanorods (GNRs), SERS enhancements of up to 1500× are achieved.We then train a ML model and achieve ≥99% classification accuracy from cellularly pure samples and ≥87% accuracy from cellularly mixed samples. We also obtain ≥90% accuracy from droplets with pathogen:blood cell ratios <1. Our combined bioprinting and SERS platform could accelerate rapid, sensitive pathogen detection in clinical, environmental, and industrial settings.

  View details for DOI 10.1021/acs.nanolett.2c03015

  View details for PubMedID 36856600

• Universal Narrowband Wavefront Shaping with High Quality Factor Meta-Reflect-Arrays. Nano letters Lin, L., Hu, J., Dagli, S., Dionne, J. A., Lawrence, M. 2023

  Abstract

  Optical metasurfaces offer unprecedented flexibility in light wave manipulation but suffer weak resonant enhancement. Tackling this problem, we experimentally unveil a new phase gradient metasurface platform made entirely from individually addressable high quality factor (high-Q) silicon meta-atoms. Composed of pairs of nearly identical nanoblocks, these meta-atoms support dipolar-guided-mode resonances that, due to the controlled suppression of radiation loss, serve as highly sensitive phase pixels when placed above a mirror. A key novelty of this platform lies in the vanishingly small structural perturbations needed to produce universal phase fronts. Having fabricated elements with Q-factor 380 and spaced by lambda/1.2, we achieve strong beam steering, up to 59% efficient, to angles 32.3°, 25.3°, and 20.9°, with variations in nanoantenna volume fractions across the metasurfaces of ≤2.6%, instead of >50% required by traditional versions. Aside from extreme sensitivity, the metasurfaces exhibit near-field intensity enhancement over 1000*. Taken together, these properties represent an exciting prospect for dynamic and nonlinear wave shaping.

  View details for DOI 10.1021/acs.nanolett.2c04621

  View details for PubMedID 36745385

• Mechanism for plasmon-generated solvated electrons. Proceedings of the National Academy of Sciences of the United States of America Al-Zubeidi, A., Ostovar, B., Carlin, C. C., Li, B. C., Lee, S. A., Chiang, W., Gross, N., Dutta, S., Misiura, A., Searles, E. K., Chakraborty, A., Roberts, S. T., Dionne, J. A., Rossky, P. J., Landes, C. F., Link, S. 2023; 120 (3): e2217035120

  Abstract

  Solvated electrons are powerful reducing agents capable of driving some of the most energetically expensive reduction reactions. Their generation under mild and sustainable conditions remains challenging though. Using near-ultraviolet irradiation under low-intensity one-photon conditions coupled with electrochemical and optical detection, we show that the yield of solvated electrons in water is increased more than 10 times for nanoparticle-decorated electrodes compared to smooth silver electrodes. Based on the simulations of electric fields and hot carrier distributions, we determine that hot electrons generated by plasmons are injected into water to form solvated electrons. Both yield enhancement and hot carrier production spectrally follow the plasmonic near-field. The ability to enhance solvated electron yields in a controlled manner by tailoring nanoparticle plasmons opens up a promising strategy for exploiting solvated electrons in chemical reactions.

  View details for DOI 10.1073/pnas.2217035120

  View details for PubMedID 36626548

• Announcing the Winner of the Inaugural Nano Letters Seed Grant Program, North America Region NANO LETTERS Dionne, J. A., Xiong, Q. 2022

  View details for DOI 10.1021/acs.nanolett.2c02394

  View details for Web of Science ID 000820334400001

  View details for PubMedID 35727891

• High-Quality-Factor Silicon-on-Lithium Niobate Metasurfaces for Electro-optically Reconfigurable Wavefront Shaping. Nano letters Klopfer, E., Dagli, S., Barton, D. 3., Lawrence, M., Dionne, J. A. 1800

  Abstract

  Dynamically reconfigurable metasurfaces promise compact and lightweight spatial light modulation for many applications, including LiDAR, AR/VR, and LiFi systems. Here, we design and computationally investigate high-quality-factor silicon-on-lithium niobate metasurfaces with electrically driven, independent control of its constituent nanobars for full phase tunability with high tuning efficiency. Free-space light couples to guided modes within each nanobar via periodic perturbations, generating quality factors exceeding 30,000 while maintaining a bar spacing of

  View details for DOI 10.1021/acs.nanolett.1c04723

  View details for PubMedID 35112873

• Lattice-Resolution, Dynamic Imaging of Hydrogen Absorption into Bimetallic AgPd Nanoparticles. ACS nano Angell, D. K., Bourgeois, B., Vadai, M., Dionne, J. A. 1800

  Abstract

  Palladium's strong reactivity and absorption affinity to H2 makes it a prime material for hydrogen-based technologies. Alloying of Pd has been used to tune its mechanical stability, catalytic activity, and absorption thermodynamics. However, atomistic mechanisms of hydrogen dissociation and intercalation are informed predominantly by theoretical calculations, owing to the difficulty in imaging dynamic metal-gas interactions at the atomic scale. Here, we use in situ environmental high resolution transmission electron microscopy to directly track the hydrogenation-induced lattice expansion within AgPd triangular nanoprisms. We investigate the thermodynamics of the system at the single particle level and show that, contrary to pure Pd nanoparticles, the AgPd system exhibits alpha/beta coexistence within single crystalline nanoparticles in equilibrium; the nanoparticle system also moves to a solid-solution loading mechanism at lower Ag content than bulk. By tracking the lattice expansion in real time during a phase transition, we see surface-limited beta phase growth, as well as rapid reorientation of the alpha/beta interface within individual particles. This secondary rate corresponds to the speed with which the beta phase can restructure and, according to our atomistic calculations, emerges from lattice strain minimization. We also observe no preferential nucleation at the sharpest nanoprism corners, contrary to classical nucleation theory. Our results achieve atomic lattice plane resolution─crucial for exploring the role of crystal defects and single atom sites on catalytic hydrogen splitting and absorption.

  View details for DOI 10.1021/acsnano.1c04602

  View details for PubMedID 35044151

• Engineering Bright and Mechanosensitive Alkaline-Earth Rare-Earth Upconverting Nanoparticles. The journal of physical chemistry letters McLellan, C. A., Siefe, C., Casar, J. R., Peng, C. S., Fischer, S., Lay, A., Parakh, A., Ke, F., Gu, X. W., Mao, W., Chu, S., Goodman, M. B., Dionne, J. A. 2022: 1547-1553

  Abstract

  Upconverting nanoparticles (UCNPs) are an emerging platform for mechanical force sensing at the nanometer scale. An outstanding challenge in realizing nanometer-scale mechano-sensitive UCNPs is maintaining a high mechanical force responsivity in conjunction with bright optical emission. This Letter reports mechano-sensing UCNPs based on the lanthanide dopants Yb3+ and Er3+, which exhibit a strong ratiometric change in emission spectra and bright emission under applied pressure. We synthesize and analyze the pressure response of five different types of nanoparticles, including cubic NaYF4 host nanoparticles and alkaline-earth host materials CaLuF, SrLuF, SrYbF, and BaLuF, all with lengths of 15 nm or less. By combining optical spectroscopy in a diamond anvil cell with single-particle brightness, we determine the noise equivalent sensitivity (GPa/√Hz) of these particles. The SrYb0.72Er0.28F@SrLuF particles exhibit an optimum noise equivalent sensitivity of 0.26 ± 0.04 GPa/√Hz. These particles present the possibility of robust nanometer-scale mechano-sensing.

  View details for DOI 10.1021/acs.jpclett.1c03841

  View details for PubMedID 35133831

• Rapid genetic screening with high quality factor metasurfaces. ArXiv Hu, J., Safir, F., Chang, K., Dagli, S., Balch, H. B., Abendroth, J. M., Dixon, J., Moradifar, P., Dolia, V., Sahoo, M. K., Pinsky, B. A., Jeffrey, S. S., Lawrence, M., Dionne, J. A. 2021

  Abstract

  Genetic analysis methods are foundational to advancing personalized and preventative medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR), next-generation sequencing (NGS), and DNA microarrays rely on fluorescence and absorbance, necessitating sample amplification or replication and leading to increased processing time and cost. Here, we introduce a label-free genetic screening platform based on high quality (high-Q) factor silicon nanoantennas functionalized with monolayers of nucleic acid fragments. Each nanoantenna exhibits substantial electromagnetic field enhancements with sufficiently localized fields to ensure isolation from neighboring resonators, enabling dense biosensor integration. We quantitatively detect complementary target sequences using DNA hybridization simultaneously for arrays of sensing elements patterned at densities of 160,000 pixels per cm$^2$. In physiological buffer, our nanoantennas exhibit average resonant quality factors of 2,200, allowing detection of two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), down to femtomolar concentrations. We also demonstrate high specificity sensing in clinical nasopharyngeal eluates within 5 minutes of sample introduction. Combined with advances in biomarker isolation from complex samples (e.g., mucus, blood, wastewater), our work provides a foundation for rapid, compact, amplification-free and high throughput multiplexed genetic screening assays spanning medical diagnostics to environmental monitoring.

  View details for PubMedID 34671699

  View details for PubMedCentralID PMC8528080

• A tribute to Mark Stockman NANOPHOTONICS Shalaev, V. M., Dionne, J., Boltasseva, A. 2021; 10 (14): 3569-3585

  View details for DOI 10.1515/nanoph-2021-0546

  View details for Web of Science ID 000712886600001

• Advancing Plasmon-Induced Selectivity in Chemical Transformations with Optically Coupled Transmission Electron Microscopy. Accounts of chemical research Swearer, D. F., Bourgeois, B. B., Angell, D. K., Dionne, J. A. 2021

  Abstract

  ConspectusNanoparticle photocatalysts are essential to processes ranging from chemical production and water purification to air filtration and surgical instrument sterilization. Photochemical reactions are generally mediated by the illumination of metallic and/or semiconducting nanomaterials, which provide the necessary optical absorption, electronic band structure, and surface faceting to drive molecular reactions. However, with reaction efficiency and selectivity dictated by atomic and molecular interactions, imaging and controlling photochemistry at the atomic scale are necessary to both understand reaction mechanisms and to improve nanomaterials for next-generation catalysts. Here, we describe how advances in plasmonics, combined with advances in electron microscopy, particularly optically coupled transmission electron microscopy (OTEM), can be used to image and control light-induced chemical transformations at the nanoscale. We focus on our group's research investigating the interaction between hydrogen gas and Pd nanoparticles, which presents an important model system for understanding both hydrogenation catalysis and hydrogen storage. The studies described in this Account primarily rely on an environmental transmission electron microscope, a tool capable of circumventing traditional TEM's high-vacuum requirements, outfitted with optical sources and detectors to couple light into and out of the microscope. First, we describe the H2 loading kinetics of individual Pd nanoparticles. When confined to sizes of less than 100 nm, single-crystalline Pd nanoparticles exhibit coherent phase transformations between the hydrogen-poor alpha-phase and hydrogen-rich beta-phase, as revealed through monitoring the bulk plasmon resonance with electron energy loss spectroscopy. Next, we describe how contrast imaging techniques, such as phase contrast STEM and displaced-aperture dark field, can be employed as real-time techniques to image phase transformations with 100 ms temporal resolution. Studies of multiply twinned Pd nanoparticles and high aspect ratio Pd nanorods demonstrate that internal strain and grain boundaries can lead to partial hydrogenation within individual nanoparticles. Finally, we describe how OTEM can be used to locally probe nanoparticle dynamics under optical excitation and in reactive chemical environments. Under illumination, multicomponent plasmonic photocatalysts consisting of a gold nanoparticle "antenna" and a Pd "reactor" show clear alpha-phase nucleation in regions close to electromagnetic "hot spots" when near plasmonic antennas. Importantly, these hot spots need not correspond to the traditionally active, energetically preferred sites of catalytic nanoparticles. Nonthermal effects imparted by plasmonic nanoparticles, including electromagnetic field enhancement and plasmon-derived hot carriers, are crucial to explaining the site selectivity observed in PdHx phase transformations under illumination. This Account demonstrates how light can contribute to selective chemical phenomena in plasmonic heterostructures, en route to sustainable, solar-driven chemical production.

  View details for DOI 10.1021/acs.accounts.1c00309

  View details for PubMedID 34492177

• Interpretable Classification of Bacterial Raman Spectra with Knockoff Wavelets. IEEE journal of biomedical and health informatics Chia, C., Sesia, M., Ho, C. S., Jeffrey, S. S., Dionne, J. A., Candes, E., Howe, R. T. 2021; PP

  Abstract

  Deep neural networks and other machine learning models are widely applied to biomedical signal data because they can detect complex patterns and compute accurate predictions. However, the difficulty of interpreting such models is a limitation, especially for applications involving high-stakes decision, including the identification of bacterial infections. This paper considers fast Raman spectroscopy data and demonstrates that a logistic regression model with carefully selected features achieves accuracy comparable to that of neural networks, while being much simpler and more transparent. Our analysis leverages wavelet features with intuitive chemical interpretations, and performs controlled variable selection with knockoffs to ensure the predictors are relevant and non-redundant. Although we focus on a particular data set, the proposed approach is broadly applicable to other types of signal data for which interpretability may be important.

  View details for DOI 10.1109/JBHI.2021.3094873

  View details for PubMedID 34232897

• Single Particle Cathodoluminescence Spectroscopy with Sub-20 nm, Electron-Stable Phosphors ACS PHOTONICS Swearer, D. F., Fischer, S., Angell, D. K., Siefe, C., Alivisatos, A., Chu, S., Dionne, J. A. 2021; 8 (6): 1539-1547

  View details for DOI 10.1021/acsphotonics.1c00235

  View details for Web of Science ID 000664306400004

• Self-Isolated Raman Lasing with a Chiral Dielectric Metasurface. Physical review letters Dixon, J., Lawrence, M., Barton, D. R., Dionne, J. 2021; 126 (12): 123201

  Abstract

  The light sources that power photonic networks are small and scalable, but they also require the incorporation of optical isolators that allow light to pass in one direction only, protecting the light source from damaging backreflections. Unfortunately, the size and complex integration of optical isolators makes small-scale and densely integrated photonic networks infeasible. Here, we overcome this limitation by designing a single device that operates both as a coherent light source and as its own optical isolator. Our design relies on high-quality-factor dielectric metasurfaces that exhibit intrinsic chirality. By carefully manipulating the geometry of the constituent silicon metaatoms, we design three-dimensionally chiral modes that act as optical spin-dependent filters. Using spin-polarized Raman scattering together with our chiral metacavity, we demonstrate Raman lasing in the forward direction, while the lasing action is suppressed by over an order of magnitude for reflected light. Our high-Q chiral metasurface design presents a new approach toward compactly isolating integrated light sources by directly tailoring the emission properties of the light source itself.

  View details for DOI 10.1103/PhysRevLett.126.123201

  View details for PubMedID 33834794

• Dynamic lattice distortions driven by surface trapping in semiconductor nanocrystals. Nature communications Guzelturk, B., Cotts, B. L., Jasrasaria, D., Philbin, J. P., Hanifi, D. A., Koscher, B. A., Balan, A. D., Curling, E., Zajac, M., Park, S., Yazdani, N., Nyby, C., Kamysbayev, V., Fischer, S., Nett, Z., Shen, X., Kozina, M. E., Lin, M., Reid, A. H., Weathersby, S. P., Schaller, R. D., Wood, V., Wang, X., Dionne, J. A., Talapin, D. V., Alivisatos, A. P., Salleo, A., Rabani, E., Lindenberg, A. M. 2021; 12 (1): 1860

  Abstract

  Nonradiative processes limit optoelectronic functionality of nanocrystals and curb their device performance. Nevertheless, the dynamic structural origins of nonradiative relaxations in such materials are not understood. Here, femtosecond electron diffraction measurements corroborated by atomistic simulations uncover transient lattice deformations accompanying radiationless electronic processes in colloidal semiconductor nanocrystals. Investigation of the excitation energy dependence in a core/shell system shows that hot carriers created by a photon energy considerably larger than the bandgap induce structural distortions at nanocrystal surfaces on few picosecond timescales associated with the localization of trapped holes. On the other hand, carriers created by a photon energy close to the bandgap of the core in the same system result in transient lattice heating that occurs on a much longer 200 picosecond timescale, dominated by an Auger heating mechanism. Elucidation of the structural deformations associated with the surface trapping of hot holes provides atomic-scale insights into the mechanisms deteriorating optoelectronic performance and a pathway towards minimizing these losses in nanocrystal devices.

  View details for DOI 10.1038/s41467-021-22116-0

  View details for PubMedID 33767138

• Lanthanide-Based Nanosensors: Refining Nanoparticle Responsiveness for Single Particle Imaging of Stimuli ACS PHOTONICS Casar, J. R., McLellan, C. A., Siefe, C., Dionne, J. A. 2021; 8 (1): 3–17

  View details for DOI 10.1021/acsphotonics.0c00894

  View details for Web of Science ID 000612567900002

• Lanthanide-Based Nanosensors: Refining Nanoparticle Responsiveness for Single Particle Imaging of Stimuli. ACS photonics Casar, J. R., McLellan, C. A., Siefe, C., Dionne, J. A. 2021; 8 (1): 3-17

  Abstract

  Lanthanide nanoparticles (LNPs) are promising sensors of chemical, mechanical, and temperature changes; they combine the narrow-spectral emission and long-lived excited states of individual lanthanide ions with the high spatial resolution and controlled energy transfer of nanocrystalline architectures. Despite considerable progress in optimizing LNP brightness and responsiveness for dynamic sensing, detection of stimuli with a spatial resolution approaching that of individual nanoparticles remains an outstanding challenge. Here, we highlight the existing capabilities and outstanding challenges of LNP sensors, en-route to nanometer-scale, single particle sensor resolution. First, we summarize LNP sensor read-outs, including changes in emission wavelength, lifetime, intensity, and spectral ratiometric values that arise from modified energy transfer networks within nanoparticles. Then, we describe the origins of LNP sensor imprecision, including sensitivity to competing conditions, interparticle heterogeneities, such as the concentration and distribution of dopant ions, and measurement noise. Motivated by these sources of signal variance, we describe synthesis characterization feedback loops to inform and improve sensor precision, and introduce noise-equivalent sensitivity as a figure of merit of LNP sensors. Finally, we project the magnitudes of chemical and pressure stimulus resolution achievable with single LNPs at nanoscale resolution. Our perspective provides a roadmap for translating ensemble LNP sensing capabilities to the single particle level, enabling nanometer-scale sensing in biology, medicine, and sustainability.

  View details for DOI 10.1021/acsphotonics.0c00894

  View details for PubMedID 34307765

  View details for PubMedCentralID PMC8297747

• Ultra-high-frequency radio-frequency acoustic molecular imaging with saline nanodroplets in living subjects. Nature nanotechnology Chen, Y. S., Zhao, Y. n., Beinat, C. n., Zlitni, A. n., Hsu, E. C., Chen, D. H., Achterberg, F. n., Wang, H. n., Stoyanova, T. n., Dionne, J. n., Gambhir, S. S. 2021

  Abstract

  Molecular imaging is a crucial technique in clinical diagnostics but it relies on radioactive tracers or strong magnetic fields that are unsuitable for many patients, particularly infants and pregnant women. Ultra-high-frequency radio-frequency acoustic (UHF-RF-acoustic) imaging using non-ionizing RF pulses allows deep-tissue imaging with sub-millimetre spatial resolution. However, lack of biocompatible and targetable contrast agents has prevented the successful in vivo application of UHF-RF-acoustic imaging. Here we report our development of targetable nanodroplets for UHF-RF-acoustic molecular imaging of cancers. We synthesize all-liquid nanodroplets containing hypertonic saline that are stable for at least 2 weeks and can produce high-intensity UHF-RF-acoustic signals. Compared with concentration-matched iron oxide nanoparticles, our nanodroplets produce at least 1,600 times higher UHF-RF-acoustic signals at the same imaging depth. We demonstrate in vivo imaging using the targeted nanodroplets in a prostate cancer xenograft mouse model expressing gastrin release protein receptor (GRPR), and show that targeting specificity is increased by more than 2-fold compared with untargeted nanodroplets or prostate cancer cells not expressing this receptor.

  View details for DOI 10.1038/s41565-021-00869-5

  View details for PubMedID 33782588

• Driving energetically unfavorable dehydrogenation dynamics with plasmonics. Science (New York, N.Y.) Sytwu, K. n., Vadai, M. n., Hayee, F. n., Angell, D. K., Dai, A. n., Dixon, J. n., Dionne, J. A. 2021; 371 (6526): 280–83

  Abstract

  Nanoparticle surface structure and geometry generally dictate where chemical transformations occur, with higher chemical activity at sites with lower activation energies. Here, we show how optical excitation of plasmons enables spatially modified phase transformations, activating otherwise energetically unfavorable sites. We have designed a crossed-bar Au-PdH x antenna-reactor system that localizes electromagnetic enhancement away from the innately reactive PdH x nanorod tips. Using optically coupled in situ environmental transmission electron microscopy, we track the dehydrogenation of individual antenna-reactor pairs with varying optical illumination intensity, wavelength, and hydrogen pressure. Our in situ experiments show that plasmons enable new catalytic sites, including dehydrogenation at the nanorod faces. Molecular dynamics simulations confirm that these new nucleation sites are energetically unfavorable in equilibrium and only accessible through tailored plasmonic excitation.

  View details for DOI 10.1126/science.abd2847

  View details for PubMedID 33446555

• High-Q nanophotonics: sculpting wavefronts with slow light NANOPHOTONICS Barton, D., Hu, J., Dixon, J., Klopfer, E., Dagli, S., Lawrence, M., Dionne, J. 2021; 10 (1): 83–88

  View details for DOI 10.1515/nanoph-2020-0510

  View details for Web of Science ID 000597359300007

• Guided-Mode-Resonant Dielectric Metasurfaces for Colorimetric Imaging of Material Anisotropy in Fibrous Biological Tissue ACS PHOTONICS Poulikakos, L., Lawrence, M., Barton, D. R., Jeffrey, S. S., Dionne, J. A. 2020; 7 (11): 3216–27

  View details for DOI 10.1021/acsphotonics.0c01303

  View details for Web of Science ID 000592916800031

• Surface-Enhanced Circular Dichroism Spectroscopy on Periodic Dual Nanostructures ACS PHOTONICS Lasa-Alonso, J., Romero Abujetas, D., Nodar, A., Dionne, J. A., Jose Saenz, J., Molina-Terriza, G., Aizpurua, J., Garcia-Etxarri, A. 2020; 7 (11): 2978–86

  View details for DOI 10.1021/acsphotonics.0c00611

  View details for Web of Science ID 000592916800006

• Fluorescence-Detected Circular Dichroism of a Chiral Molecular Monolayer with Dielectric Metasurfaces. Journal of the American Chemical Society Solomon, M. L., Abendroth, J. M., Poulikakos, L. V., Hu, J., Dionne, J. A. 2020

  Abstract

  Strong enhancement of molecular circular dichroism (CD) has the potential to enable efficient asymmetric photolysis, a method of chiral separation that has conventionally been impeded by insufficient yield and low enantiomeric excess. Here, we study experimentally how predicted enhancements in optical chirality density near resonant silicon nanodisks boost CD. We use fluorescence-detected circular dichroism (FDCD) spectroscopy to measure indirectly the differential absorption of circularly polarized light by a monolayer of optically active molecules functionalized to silicon nanodisk arrays. Importantly, the molecules and nanodisk antennas have spectrally coincident resonances, and our fluorescence technique allows us to deconvolute absorption in the nanodisks from the molecules. We find that enhanced FDCD signals depend on nanophotonic resonances, in good agreement with simulated differential absorption and optical chirality density, while no signal is detected from molecules adsorbed on featureless silicon surfaces. These results verify the potential of nanophotonic platforms to be used for asymmetric photolysis with lower energy requirements.

  View details for DOI 10.1021/jacs.0c07140

  View details for PubMedID 33048539

• Helicity-Preserving Metasurfaces for Magneto-Optical Enhancement in Ferromagnetic [Pt/Co](N)Films ADVANCED OPTICAL MATERIALS Abendroth, J. M., Solomon, M. L., Barton, D. R., El Hadri, M. S., Fullerton, E. E., Dionne, J. A. 2020

  View details for DOI 10.1002/adom.202001420

  View details for Web of Science ID 000572078500001

• Bright infrared to ultraviolet and visible upconversion in small alkaline earth-based nanoparticles with biocompatible CaF2 shells. Angewandte Chemie (International ed. in English) Fischer, S., Siefe, C., Swearer, D. F., McLellan, C. A., Alivisatos, A. P., Dionne, J. A. 2020

  Abstract

  Upconverting nanoparticles (UCNPs) are promising candidates for photon-driven reactions, including light-triggered drug delivery, photodynamic therapy, and photocatalysis. Here, we investigate the NIR to UV and visible emission of sub-15 nm alkaline-earth rare-earth fluoride UCNPs (M 1-x Ln x F 2+x, MLnF) with a CaF 2 shell. We synthesize 8 alkaline-earth host materials doped with Yb 3+ and Tm 3+ , with alkaline-earth (M) spanning Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. We explore UCNP composition, size, and lanthanide doping dependent emission, focusing on upconversion quantum yield (UCQY) and UV emission. UCQY values of 2.46% at 250 W/cm 2 are achieved with 14.5 nm SrLuF@CaF 2 particles, with 7.3% of total emission in the UV. In 10.9 nm SrYbF:1%Tm 3+ @CaF 2 particles, UV emission increased to 9.9% with UCQY at 1.14%. We demonstrate dye degradation under NIR illumination using SrYbF:1%Tm 3+ @CaF 2 , highlighting the efficiency of these UCNPs and their ability to trigger photoprocesses.

  View details for DOI 10.1002/anie.202007683

  View details for PubMedID 32841471

• 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

• Electron- and light-induced stimulated Raman spectroscopy for nanoscale molecular mapping PHYSICAL REVIEW B Saleh, A. A. E., Angell, D. K., Dionne, J. A. 2020; 102 (8)

  View details for DOI 10.1103/PhysRevB.102.085406

  View details for Web of Science ID 000556225900004

• Toward rapid infectious disease diagnosis with advances in surface-enhanced Raman spectroscopy. The Journal of chemical physics Tadesse, L. F., Safir, F., Ho, C., Hasbach, X., Khuri-Yakub, B. P., Jeffrey, S. S., Saleh, A. A., Dionne, J. 2020; 152 (24): 240902

  Abstract

  In a pandemic era, rapid infectious disease diagnosis is essential. Surface-enhanced Raman spectroscopy (SERS) promises sensitive and specific diagnosis including rapid point-of-care detection and drug susceptibility testing. SERS utilizes inelastic light scattering arising from the interaction of incident photons with molecular vibrations, enhanced by orders of magnitude with resonant metallic or dielectric nanostructures. While SERS provides a spectral fingerprint of the sample, clinical translation is lagged due to challenges in consistency of spectral enhancement, complexity in spectral interpretation, insufficient specificity and sensitivity, and inefficient workflow from patient sample collection to spectral acquisition. Here, we highlight the recent, complementary advances that address these shortcomings, including (1) design of label-free SERS substrates and data processing algorithms that improve spectral signal and interpretability, essential for broad pathogen screening assays; (2) development of new capture and affinity agents, such as aptamers and polymers, critical for determining the presence or absence of particular pathogens; and (3) microfluidic and bioprinting platforms for efficient clinical sample processing. We also describe the development of low-cost, point-of-care, optical SERS hardware. Our paper focuses on SERS for viral and bacterial detection, in hopes of accelerating infectious disease diagnosis, monitoring, and vaccine development. With advances in SERS substrates, machine learning, and microfluidics and bioprinting, the specificity, sensitivity, and speed of SERS can be readily translated from laboratory bench to patient bedside, accelerating point-of-care diagnosis, personalized medicine, and precision health.

  View details for DOI 10.1063/1.5142767

  View details for PubMedID 32610995

• Revealing multiple classes of stable quantum emitters in hexagonal boron nitride with correlated optical and electron microscopy. Nature materials Hayee, F., Yu, L., Zhang, J. L., Ciccarino, C. J., Nguyen, M., Marshall, A. F., Aharonovich, I., Vuckovic, J., Narang, P., Heinz, T. F., Dionne, J. A. 2020

  Abstract

  Defects in hexagonal boron nitride (hBN) exhibit high-brightness, room-temperature quantum emission, but their large spectral variability and unknown local structure challenge their technological utility. Here, we directly correlate hBN quantum emission with local strain using a combination of photoluminescence (PL), cathodoluminescence (CL) and nanobeam electron diffraction. Across 40 emitters, we observe zero phonon lines (ZPLs) in PL and CL ranging from 540 to 720nm. CL mapping reveals that multiple defects and distinct defect species located within an optically diffraction-limited region can each contribute to the observed PL spectra. Local strain maps indicate that strain is not required to activate the emitters and is not solely responsible for the observed ZPL spectral range. Instead, at least four distinct defect classes are responsible for the observed emission range, and all four classes are stable upon both optical and electron illumination. Our results provide a foundation for future atomic-scale optical characterization of colour centres.

  View details for DOI 10.1038/s41563-020-0616-9

  View details for PubMedID 32094492

• Plasmonic and Electrostatic Interactions Enable Uniformly Enhanced Liquid Bacterial Surface-Enhanced Raman Scattering (SERS). Nano letters Tadesse, L. F., Ho, C. S., Chen, D. H., Arami, H. n., Banaei, N. n., Gambhir, S. S., Jeffrey, S. S., Saleh, A. A., Dionne, J. n. 2020

  Abstract

  Surface-enhanced Raman spectroscopy (SERS) is a promising cellular identification and drug susceptibility testing platform, provided it can be performed in a controlled liquid environment that maintains cell viability. We investigate bacterial liquid-SERS, studying plasmonic and electrostatic interactions between gold nanorods and bacteria that enable uniformly enhanced SERS. We synthesize five nanorod sizes with longitudinal plasmon resonances ranging from 670 to 860 nm and characterize SERS signatures of Gram-negative Escherichia coli and Serratia marcescens and Gram-positive Staphylococcus aureus and Staphylococcus epidermidis bacteria in water. Varying the concentration of bacteria and nanorods, we achieve large-area SERS enhancement that is independent of nanorod resonance and bacteria type; however, bacteria with higher surface charge density exhibit significantly higher SERS signal. Using cryo-electron microscopy and zeta potential measurements, we show that the higher signal results from attraction between positively charged nanorods and negatively charged bacteria. Our robust liquid-SERS measurements provide a foundation for bacterial identification and drug testing in biological fluids.

  View details for DOI 10.1021/acs.nanolett.0c03189

  View details for PubMedID 32914987

• High Quality Factor Dielectric Metasurfaces for Ultraviolet Circular Dichroism Spectroscopy ACS PHOTONICS Hu, J., Lawrence, M., Dionne, J. A. 2020; 7 (1): 36–42

  View details for DOI 10.1021/acsphotonics.9b01352

  View details for Web of Science ID 000508475800004

• Nanophotonic Platforms for Chiral Sensing and Separation. Accounts of chemical research Solomon, M. L., Saleh, A. A., Poulikakos, L. V., Abendroth, J. M., Tadesse, L. F., Dionne, J. A. 2020

  Abstract

  Chirality in Nature can be found across all length scales, from the subatomic to the galactic. At the molecular scale, the spatial dissymmetry in the atomic arrangements of pairs of mirror-image molecules, known as enantiomers, gives rise to fascinating and often critical differences in chemical and physical properties. With increasing hierarchical complexity, protein function, cell communication, and organism health rely on enantioselective interactions between molecules with selective handedness. For example, neurodegenerative and neuropsychiatric disorders including Alzheimer's and Parkinson's diseases have been linked to distortion of chiral-molecular structure. Moreover, d-amino acids have become increasingly recognized as potential biomarkers, necessitating comprehensive analytical methods for diagnosis that are capable of distinguishing l- from d-forms and quantifying trace concentrations of d-amino acids. Correspondingly, many pharmaceuticals and agrochemicals consist of chiral molecules that target particular enantioselective pathways. Yet, despite the importance of molecular chirality, it remains challenging to sense and to separate chiral compounds. Chiral-optical spectroscopies are designed to analyze the purity of chiral samples, but they are often insensitive to the trace enantiomeric excess that might be present in a patient sample, such as blood, urine, or sputum, or pharmaceutical product. Similarly, existing separation schemes to enable enantiopure solutions of chiral products are inefficient or costly. Consequently, most pharmaceuticals or agrochemicals are sold as racemic mixtures, with reduced efficacy and potential deleterious impacts. Recent advances in nanophotonics lay the foundation toward highly sensitive and efficient chiral detection and separation methods. In this Account, we highlight our group's effort to leverage nanoscale chiral light-matter interactions to detect, characterize, and separate enantiomers, potentially down to the single molecule level. Notably, certain resonant nanostructures can significantly enhance circular dichroism for improved chiral sensing and spectroscopy as well as high-yield enantioselective photochemistry. We first describe how achiral metallic and dielectric nanostructures can be utilized to increase the local optical chirality density by engineering the coupling between electric and magnetic optical resonances. While plasmonic nanoparticles locally enhance the optical chirality density, high-index dielectric nanoparticles can enable large-volume and uniform-sign enhancements in the optical chirality density. By overlapping these electric and magnetic resonances, local chiral fields can be enhanced by several orders of magnitude. We show how these design rules can enable high-yield enantioselective photochemistry and project a 2000-fold improvement in the yield of a photoionization reaction. Next, we discuss how optical forces can enable selective manipulation and separation of enantiomers. We describe the design of low-power enantioselective optical tweezers with the ability to trap sub-10 nm dielectric particles. We also characterize their chiral-optical forces with high spatial and force resolution using combined optical and atomic force microscopy. These optical tweezers exhibit an enantioselective optical force contrast exceeding 10 pN, enabling selective attraction or repulsion of enantiomers based on the illumination polarization. Finally, we discuss future challenges and opportunities spanning fundamental research to technology translation. Disease detection in the clinic as well as pharmaceutical and agrochemical industrial applications requiring large-scale, high-throughput production will gain particular benefit from the simplicity and relative low cost that nanophotonic platforms promise.

  View details for DOI 10.1021/acs.accounts.9b00460

  View details for PubMedID 31913015

• Dynamic Focusing with High-Quality-Factor Metalenses. Nano letters Klopfer, E. n., Lawrence, M. n., Barton, D. R., Dixon, J. n., Dionne, J. A. 2020

  Abstract

  Metasurface lenses provide an ultrathin platform in which to focus light, but weak light-matter interactions limit their dynamic tunability. Here we design submicron-thick, ultrahigh quality factor (high-Q) metalenses that enable dynamic modulation of the focal length and intensity. Using full-field simulations, we show that quality factors exceeding 5000 can be generated by including subtle, periodic perturbations within the constituent Si nanoantennas. Such high-Q resonances enable lens modulation based on the nonlinear Kerr effect, with focal lengths varying from 4 to 6.5 μm and focal intensities decreasing by half as input intensity increases from 0.1 to 1 mW/μm2. We also show how multiple high-Q resonances can be embedded in the lens response through judicious placement of the perturbations. Our high-Q lens design, with quality factors 2 orders of magnitude higher than existing lens designs, provides a foundation for reconfigurable, multiplexed, and hyperspectral metasurface imaging platforms.

  View details for DOI 10.1021/acs.nanolett.0c01359

  View details for PubMedID 32497434

• Alkaline-earth Rare-earth Upconverting Nanoparticles as Bio-compatible Mechanical Force Sensors McLellan, C. A., Siefe, C. P., Fischer, S., Casar, J. R., Swearer, D. F., Goodman, M. B., Dionne, J. A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090003343

• A Core-Shell-Shell Nanoparticle Architecture Towards Bright Upconversion and Improved Forster Resonant Energy Transfer Siefe, C., Mehlenbacher, R. D., Peng, C., Zhang, Y., Fischer, S., Lay, A., McLellan, C. A., Alivisatos, A., Chu, S., Dionne, J. A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090002272

• Sub-20 nm Core-Shell-Shell Nanoparticles for Bright Upconversion and Enhanced Forster Resonant Energy Transfer. Journal of the American Chemical Society Siefe, C., Mehlenbacher, R. D., Peng, C. S., Zhang, Y., Fischer, S., Lay, A., McLellan, C. A., Alivisatos, A. P., Chu, S., Dionne, J. A. 2019

  Abstract

  Upconverting nanoparticles provide valuable benefits as optical probes for bioimaging and Forster resonant energy transfer (FRET) due to their high signal-to-noise ratio, photostability, and biocompatibility; yet, making nanoparticles small yields a significant decay in brightness due to increased surface quenching. Approaches to improve the brightness of UCNPs exist but often require increased nanoparticle size. Here we present a unique core-shell-shell nanoparticle architecture for small (sub-20 nm), bright upconversion with several key features: (1) maximal sensitizer concentration in the core for high near-infrared absorption, (2) efficient energy transfer between core and interior shell for strong emission, and (3) emitter localization near the nanoparticle surface for efficient FRET. This architecture consists of beta-NaYbF4 (core) @NaY0.8-xErxGd0.2F4 (interior shell) @NaY0.8Gd0.2F4 (exterior shell), where sensitizer and emitter ions are partitioned into core and interior shell, respectively. Emitter concentration is varied (x = 1, 2, 5, 10, 20, 50, and 80%) to investigate influence on single particle brightness, upconversion quantum yield, decay lifetimes, and FRET coupling. We compare these seven samples with the field-standard core-shell architecture of beta-NaY0.58Gd0.2Yb0.2Er0.02F4 (core) @NaY0.8Gd0.2F4 (shell), with sensitizer and emitter ions codoped in the core. At a single particle level, the core-shell-shell design was up to 2-fold brighter than the standard core-shell design. Further, by coupling a fluorescent dye to the surface of the two different architectures, we demonstrated up to 8-fold improved emission enhancement with the core-shell-shell compared to the core-shell design. We show how, given proper consideration for emitter concentration, we can design a unique nanoparticle architecture to yield comparable or improved brightness and FRET coupling within a small volume.

  View details for DOI 10.1021/jacs.9b09571

  View details for PubMedID 31592655

• Light years: Combined optical and environmental electron microscopy to visualize dynamic photochemical processes with atomic-scale resolution Dionne, J. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061504078

• All-dielectric, mid-infrared metasurfaces for vibrational circular dichroism enhancement Abendroth, J., Hu, J., Poulikakos, L., Solomon, M., Lawrence, M., Dionne, J. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525055501500

• Aqueous-phase nanophotonic materials to probe molecular and cellular processes Dionne, J. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061502382

• Towards all-optical chiral resolution and few-molecule circular dichroism spectroscopy with dielectric metasurfaces Dionne, J., Solomon, M., Hu, J., Abendroth, J., Lawrence, M., Poulikakos, L. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061503599

• Nanoscale nonreciprocity via photon-spin-polarized stimulated Raman scattering. Nature communications Lawrence, M., Dionne, J. A. 2019; 10 (1): 3297

  Abstract

  Time reversal symmetry stands as a fundamental restriction on the vast majority of optical systems and devices. The reciprocal nature of Maxwell's equations in linear, time-invariant media adds complexity and scale to photonic diodes, isolators, circulators and also sets fundamental efficiency limits on optical energy conversion. Though many theoretical proposals and low frequency demonstrations of nonreciprocity exist, Faraday rotation remains the only known nonreciprocal mechanism that persists down to the atomic scale. Here, we present photon-spin-polarized stimulated Raman scattering as a new nonreciprocal optical phenomenon which has, in principle, no lower size limit. Exploiting this process, we numerically demonstrate nanoscale nonreciprocal transmission of free-space beams at near-infrared frequencies with a 250nm thick silicon metasurface as well as a fully-subwavelength plasmonic gap nanoantenna. In revealing all-optical spin-splitting, our results provide a foundation for compact nonreciprocal communication and computing technologies, from nanoscale optical isolators and full-duplex nanoantennas to topologically-protected networks.

  View details for DOI 10.1038/s41467-019-11175-z

  View details for PubMedID 31341164

• Optically Robust and Biocompatible Mechanosensitive Upconverting Nanoparticles. ACS central science Lay, A., Sheppard, O. H., Siefe, C., McLellan, C. A., Mehlenbacher, R. D., Fischer, S., Goodman, M. B., Dionne, J. A. 2019; 5 (7): 1211-1222

  Abstract

  Upconverting nanoparticles (UCNPs) are promising tools for background-free imaging and sensing. However, their usefulness for in vivo applications depends on their biocompatibility, which we define by their optical performance in biological environments and their toxicity in living organisms. For UCNPs with a ratiometric color response to mechanical stress, consistent emission intensity and color are desired for the particles under nonmechanical stimuli. Here, we test the biocompatibility and mechanosensitivity of α-NaYF4:Yb,Er@NaLuF4 nanoparticles. First, we ligand-strip these particles to render them dispersible in aqueous media. Then, we characterize their mechanosensitivity (∼30% in the red-to-green spectral ratio per GPa), which is nearly 3-fold greater than those coated in oleic acid. We next design a suite of ex vivo and in vivo tests to investigate their structural and optical properties under several biorelevant conditions: over time in various buffers types, as a function of pH, and in vivo along the digestive tract of Caenorhabditis elegans worms. Finally, to ensure that the particles do not perturb biological function in C. elegans, we assess the chronic toxicity of nanoparticle ingestion using a reproductive brood assay. In these ways, we determine that mechanosensitive UCNPs are biocompatible, i.e., optically robust and nontoxic, for use as in vivo sensors to study animal digestion.

  View details for DOI 10.1021/acscentsci.9b00300

  View details for PubMedID 31403071

  View details for PubMedCentralID PMC6661856

• Small Alkaline-Earth-based Core/Shell Nanoparticles for Efficient Upconversion NANO LETTERS Fischer, S., Mehlenbacher, R. D., Lay, A., Siefe, C., Alivisatos, A., Dionne, J. A. 2019; 19 (6): 3878–85

  View details for DOI 10.1021/acs.nanolett.9b01057

  View details for Web of Science ID 000471834900063

• Bimetallic nanostructures: combining plasmonic and catalytic metals for photocatalysis ADVANCES IN PHYSICS-X Sytwu, K., Vadai, M., Dionne, J. A. 2019; 4 (1)

  View details for DOI 10.1080/23746149.2019.1619480

  View details for Web of Science ID 000471185100001

• Bright sub-20-nm cathodoluminescent nanoprobes for electron microscopy NATURE NANOTECHNOLOGY Prigozhin, M. B., Maurer, P. C., Courtis, A. M., Liu, N., Wisser, M. D., Siefe, C., Tian, B., Chan, E., Song, G., Fischer, S., Aloni, S., Ogletree, D., Barnard, E. S., Joubert, L., Rao, J., Alivisatos, A., Macfarlane, R. M., Cohen, B. E., Cui, Y., Dionne, J. A., Chu, S. 2019; 14 (5): 420-+

  View details for DOI 10.1038/s41565-019-0395-0

  View details for Web of Science ID 000467053100016

• Light years: Combined optical and environmental electron microscopy to visualize photonic processes with atomic-scale resolution Dionne, J. A. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000478860504348

• Optical Helicity and Optical Chirality in Free Space and in the Presence of Matter Symmetry 2019, 11(9) Poulikakos, L. V., Dionne, J. A., Garcia-Etxarri, A. 2019; 11 (9)

  View details for DOI 10.3390/sym11091113

• Enantiospecific Optical Enhancement of Chiral Sensing and Separation with Dielectric Metasurfaces ACS PHOTONICS Solomon, M. L., Hu, J., Lawrence, M., Garcia-Etxarri, A., Dionne, J. A. 2019; 6 (1): 43–49

  View details for DOI 10.1021/acsphotonics.8b01365

  View details for Web of Science ID 000456350400007

• Unraveling the origin of chirality from plasmonic nanoparticle-protein complexes. Science (New York, N.Y.) Zhang, Q. n., Hernandez, T. n., Smith, K. W., Hosseini Jebeli, S. A., Dai, A. X., Warning, L. n., Baiyasi, R. n., McCarthy, L. A., Guo, H. n., Chen, D. H., Dionne, J. A., Landes, C. F., Link, S. n. 2019; 365 (6460): 1475–78

  Abstract

  Plasmon-coupled circular dichroism has emerged as a promising approach for ultrasensitive detection of biomolecular conformations through coupling between molecular chirality and surface plasmons. Chiral nanoparticle assemblies without chiral molecules present also have large optical activities. We apply single-particle circular differential scattering spectroscopy coupled with electron imaging and simulations to identify both structural chirality of plasmonic aggregates and plasmon-coupled circular dichroism induced by chiral proteins. We establish that both chiral aggregates and just a few proteins in interparticle gaps of achiral assemblies are responsible for the ensemble signal, but single nanoparticles do not contribute. We furthermore find that the protein plays two roles: It transfers chirality to both chiral and achiral plasmonic substrates, and it is also responsible for the chiral three-dimensional assembly of nanorods. Understanding these underlying factors paves the way toward sensing the chirality of single biomolecules.

  View details for DOI 10.1126/science.aax5415

  View details for PubMedID 31604278

• Rapid identification of pathogenic bacteria using Raman spectroscopy and deep learning. Nature communications Ho, C. S., Jean, N. n., Hogan, C. A., Blackmon, L. n., Jeffrey, S. S., Holodniy, M. n., Banaei, N. n., Saleh, A. A., Ermon, S. n., Dionne, J. n. 2019; 10 (1): 4927

  Abstract

  Raman optical spectroscopy promises label-free bacterial detection, identification, and antibiotic susceptibility testing in a single step. However, achieving clinically relevant speeds and accuracies remains challenging due to weak Raman signal from bacterial cells and numerous bacterial species and phenotypes. Here we generate an extensive dataset of bacterial Raman spectra and apply deep learning approaches to accurately identify 30 common bacterial pathogens. Even on low signal-to-noise spectra, we achieve average isolate-level accuracies exceeding 82% and antibiotic treatment identification accuracies of 97.0±0.3%. We also show that this approach distinguishes between methicillin-resistant and -susceptible isolates of Staphylococcus aureus (MRSA and MSSA) with 89±0.1% accuracy. We validate our results on clinical isolates from 50 patients. Using just 10 bacterial spectra from each patient isolate, we achieve treatment identification accuracies of 99.7%. Our approach has potential for culture-free pathogen identification and antibiotic susceptibility testing, and could be readily extended for diagnostics on blood, urine, and sputum.

  View details for DOI 10.1038/s41467-019-12898-9

  View details for PubMedID 31666527

• In-situ observation of plasmon-controlled photocatalytic dehydrogenation of individual palladium nanoparticles NATURE COMMUNICATIONS Vadai, M., Angell, D. K., Hayee, F., Sytwu, K., Dionne, J. A. 2018; 9

  View details for DOI 10.1038/s41467-018-07108-x

  View details for Web of Science ID 000449363900007

• In-situ observation of plasmon-controlled photocatalytic dehydrogenation of individual palladium nanoparticles. Nature communications Vadai, M., Angell, D. K., Hayee, F., Sytwu, K., Dionne, J. A. 2018; 9 (1): 4658

  Abstract

  Plasmonic nanoparticle catalysts offer improved light absorption and carrier transport compared to traditional photocatalysts. However, it remains unclear how plasmonic excitation affects multi-step reaction kinetics and promotes site-selectivity. Here, we visualize a plasmon-induced reaction at the sub-nanoparticle level in-situ and in real-time. Using an environmental transmission electron microscope combined with light excitation, we study the photocatalytic dehydrogenation of individual palladium nanocubes coupled to gold nanoparticles with sub-2 nanometer spatial resolution. We find that plasmons increase the rate of distinct reaction steps with unique time constants; enable reaction nucleation at specific sites closest to the electromagnetic hot spots; and appear to open a new reaction pathway that is not observed without illumination. These effects are explained by plasmon-mediated population of excited-state hybridized palladium-hydrogen orbitals. Our results help elucidate the role of plasmons in light-driven photochemical transformations, en-route to design of site-selective and product-specific photocatalysts.

  View details for PubMedID 30405133

• Equilibration of Photogenerated Charge Carriers in Plasmonic Core@Shell Nanoparticles JOURNAL OF PHYSICAL CHEMISTRY C Parente, M., Sheikholeslami, S., Naik, G., Dionne, J. A., Baldi, A. 2018; 122 (41): 23631–38

  View details for DOI 10.1021/acs.jpcc.8b05003

  View details for Web of Science ID 000448087900042

• Active polarization control with a parity-time-symmetric plasmonic resonator PHYSICAL REVIEW B Baum, B., Lawrence, M., Barton, D., Dionne, J., Alaeian, H. 2018; 98 (16)

  View details for DOI 10.1103/PhysRevB.98.165418

  View details for Web of Science ID 000447184600006

• Visualizing Facet-Dependent Hydrogenation Dynamics in Individual Palladium Nanoparticles. Nano letters Sytwu, K., Hayee, F., Narayan, T. C., Koh, A. L., Sinclair, R., Dionne, J. A. 2018

  Abstract

  Surface faceting in nanoparticles can profoundly impact the rate and selectivity of chemical transformations. However, the precise role of surface termination can be challenging to elucidate because many measurements are performed on ensembles of particles and do not have sufficient spatial resolution to observe reactions at the single and subparticle level. Here, we investigate solute intercalation in individual palladium hydride nanoparticles with distinct surface terminations. Using a combination of diffraction, electron energy loss spectroscopy, and dark-field contrast in an environmental transmission electron microscope (TEM), we compare the thermodynamics and directly visualize the kinetics of 40-70 nm {100}-terminated cubes and {111}-terminated octahedra with approximately 2 nm spatial resolution. Despite their distinct surface terminations, both particle morphologies nucleate the new phase at the tips of the particle. However, whereas the hydrogenated phase-front must rotate from [111] to [100] to propagate in cubes, the phase-front can propagate along the [100], [110], and [111] directions in octahedra. Once the phase-front is established, the interface propagates linearly with time and is rate-limited by surface-to-subsurface diffusion and/or the atomic rearrangements needed to accommodate lattice strain. Following nucleation, both particle morphologies take approximately the same time to reach equilibrium, hydrogenating at similar pressures and without equilibrium phase coexistence. Our results highlight the importance of low-coordination number sites and strain, more so than surface faceting, in governing solute-driven reactions.

  View details for PubMedID 30148640

• Mechanosensitive upconverting nanoparticles for visualizing mechanical forces in vivo Lay, A., Siefe, C., Fischer, S., Mehlenbacher, R., Das, A., Nekimken, A., Ke, F., Mao, W., Pruitt, B., Cohen, B., Alivisatos, P., Goodman, M., Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447600003857

• Nanophotonic approaches to observe and control atomic and molecular processes Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609102530

• Plasmonic approaches for visualizing and controlling intercalation-driven phase transformations Dionne, J., Hayee, F., Vadai, M., Angell, D., Sytwu, K. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609103687

• In-situ visualization of plasmon-induced hydrogenation reactions in individual palladium nanocubes Vadai, M., Angell, D., Hayee, F., Sytwu, K., Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447600004268

• Electric field sensitive upconverting nanoparticles: Toward background free in vivo action potential imaging Mehlenbacher, R., Siefe, C., Lay, A., Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447600004298

• Exploring nanoparticle architecture to design small, bright upconverting nanoparticles for bioimaging Siefe, C., Mehlenbacher, R., Fischer, S., Lay, A., Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447600003855

• In-situ observation of plasmon-driven hydrogenation reactions within Au@Pd coreshell nanoparticles Sytwu, K., Vadai, M., Hayee, F., Koh, A., Sinclair, R., Dionne, J. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447600004349

• Response to "Comment on 'Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers'" ACS PHOTONICS Zhao, Y., Dionne, J. 2018; 5 (6): 2535–36

  View details for DOI 10.1021/acsphotonics.7b01610

  View details for Web of Science ID 000436211900059

• The social scientist NATURE NANOTECHNOLOGY Dionne, J. A. 2018; 13 (5): 434

  View details for PubMedID 29728664

• Improving Quantum Yield of Upconverting Nanoparticles in Aqueous Media via Emission Sensitization NANO LETTERS Wisser, M. D., Fischer, S., Siefe, C., Alivisatos, A., Salleo, A., Dionne, J. A. 2018; 18 (4): 2689–95

  Abstract

  We demonstrate a facile method to improve upconversion quantum yields in Yb,Er-based nanoparticles via emission dye-sensitization. Using the commercially available dye ATTO 542, chosen for its high radiative rate and significant spectral overlap with the green emission of Er3+, we decorate the surfaces of sub-25 nm hexagonal-phase Na(Y/Gd/Lu)0.8F4:Yb0.18Er0.02 upconverting nanoparticles with varying dye concentrations. Upconversion photoluminescence and absorption spectroscopy provide experimental confirmation of energy transfer to and emission from the dye molecules. Upconversion quantum yield is observed to increase with dye sensitization, with the highest enhancement measured for the smallest particles investigated (10.9 nm in diameter); specifically, these dye-decorated particles are more than 2× brighter than are unmodified, organic-soluble nanoparticles and more than 10× brighter than are water-soluble nanoparticles. We also observe 3× lifetime reductions with dye adsorption, confirming the quantum yield enhancement to result from the high radiative rate of the dye. The approach detailed in this work is widely implementable, renders the nanoparticles water-soluble, and most significantly improves sub-15 nm nanoparticles, making our method especially attractive for biological imaging applications.

  View details for PubMedID 29589449

• Roadmap on plasmonics JOURNAL OF OPTICS Stockman, M. I., Kneipp, K., Bozhevolnyi, S. I., Saha, S., Dutta, A., Ndukaife, J., Kinsey, N., Reddy, H., Guler, U., Shalaev, V. M., Boltasseva, A., Gholipour, B., Krishnamoorthy, H. N. S., MacDonald, K. F., Soci, C., Zheludev, N. I., Savinov, V., Singh, R., Gross, P., Lienau, C., Vadai, M., Solomon, M. L., Barton, D. R., Lawrence, M., Dionne, J. A., Boriskina, S. V., Esteban, R., Aizpurua, J., Zhang, X., Yang, S., Wang, D., Wang, W., Odom, T. W., Accanto, N., de Roque, P. M., Hancu, I. M., Piatkowski, L., van Hulst, N. F., Kling, M. F. 2018; 20 (4)

  View details for DOI 10.1088/2040-8986/aaa114

  View details for Web of Science ID 000447428100001

• Chemically Responsive Elastomers Exhibiting Unity-Order Refractive Index Modulation. Advanced materials (Deerfield Beach, Fla.) Wu, D. M., Solomon, M. L., Naik, G. V., Garcia-Etxarri, A., Lawrence, M., Salleo, A., Dionne, J. A. 2018; 30 (7)

  Abstract

  Chameleons are masters of light, expertly changing their color, pattern, and reflectivity in response to their environment. Engineered materials that share this tunability can be transformative, enabling active camouflage, tunable holograms, and novel colorimetric medical sensors. While progress has been made in creating artificial chameleon skin, existing schemes often require external power, are not continuously tunable, and may prove too stiff or bulky for applications. Here, a chemically tunable, large-area metamaterial is demonstrated that accesses a wide range of colors and refractive indices. An ordered monolayer of nanoresonators is fabricated, then its optical response is dynamically tuned by infiltrating its polymer substrate with solvents. The material shows a strong magnetic response with a dependence on resonator spacing that leads to a highly tunable effective permittivity, permeability, and refractive index spanning negative and positive values. The unity-order index tuning exceeds that of traditional electro-optic and photochromic materials and is robust to cycling, providing a path toward programmable optical elements and responsive light routing.

  View details for PubMedID 29315902

• Nonreciprocal Flat Optics with Silicon Metasurfaces NANO LETTERS Lawrence, M., Barton, D. R., Dionne, J. A. 2018; 18 (2): 1104–9

  Abstract

  Metasurfaces enable almost complete control of light through ultrathin, subwavelength surfaces by locally and abruptly altering the scattered phase. To date, however, all metasurfaces obey time-reversal symmetry, meaning that forward and backward traveling waves will trace identical paths when being reflected, refracted, or diffracted. Here, we use full-field calculations to design a passive metasurface for nonreciprocal transmission of both direct and anomalously refracted near-infrared light over nanoscale optical path lengths. The metasurface consists of a 100 nm-thick, periodically patterned Si slab. Owing to the high-quality-factor resonances of the metasurface and the inherent Kerr nonlinearities of Si, this structure acts as an optical diode for free-space optical signals. This structure also exhibits nonreciprocal anomalous refraction with appropriate patterning to form a phase gradient metasurface. Compared to existing schemes for breaking time-reversal symmetry, our platform enables subwavelength nonreciprocity for arbitrary free-space optical inputs and provides a straightforward path to experimental realization. The concept is also generalizable to other metasurface functions, providing a foundation for one-way lensing and holography.

  View details for PubMedID 29369641

• Nanomaterials for in vivo imaging of mechanical forces and electrical fields NATURE REVIEWS MATERIALS Mehlenbacher, R. D., Kolbl, R., Lay, A., Dionne, J. A. 2018; 3 (2)

  View details for DOI 10.1038/natrevmats.2017.80

  View details for Web of Science ID 000426604800006

• Broadband and wide-angle nonreciprocity with a non-Hermitian metamaterial PHYSICAL REVIEW B Barton, D. R., Alaeian, H., Lawrence, M., Dionne, J. 2018; 97 (4)

  View details for DOI 10.1103/PhysRevB.97.045432

  View details for Web of Science ID 000423433700008

• Bright, Mechanosensitive Upconversion with Cubic-Phase Heteroepitaxial Core-Shell Nanoparticles. Nano letters Lay, A. n., Siefe, C. n., Fischer, S. n., Mehlenbacher, R. D., Ke, F. n., Mao, W. L., Alivisatos, A. P., Goodman, M. B., Dionne, J. A. 2018

  Abstract

  Lanthanide-doped nanoparticles are an emerging class of optical sensors, exhibiting sharp emission peaks, high signal-to-noise ratio, photostability, and a ratiometric color response to stress. The same centrosymmetric crystal field environment that allows for high mechanosensitivity in the cubic-phase (α), however, contributes to low upconversion quantum yield (UCQY). In this work, we engineer brighter mechanosensitive upconverters using a core-shell geometry. Sub-25 nm α-NaYF4:Yb,Er cores are shelled with an optically inert surface passivation layer of ∼4.5 nm thickness. Using different shell materials, including NaGdF4, NaYF4, and NaLuF4, we study how compressive to tensile strain influences the nanoparticles' imaging and sensing properties. All core-shell nanoparticles exhibit enhanced UCQY, up to 0.14% at 150 W/cm2, which rivals the efficiency of unshelled hexagonal-phase (β) nanoparticles. Additionally, strain at the core-shell interface can tune mechanosensitivity. In particular, the compressive Gd shell results in the largest color response from yellow-green to orange or, quantitatively, a change in the red to green ratio of 12.2 ± 1.2% per GPa. For all samples, the ratiometric readouts are consistent over three pressure cycles from ambient to 5 GPa. Therefore, heteroepitaxial shelling significantly improves signal brightness without compromising the core's mechano-sensing capabilities and further, promotes core-shell cubic-phase nanoparticles as upcoming in vivo and in situ optical sensors.

  View details for PubMedID 29927609

• In-situ visualization of solute-driven phase coexistence within individual nanorods. Nature communications Hayee, F. n., Narayan, T. C., Nadkarni, N. n., Baldi, A. n., Koh, A. L., Bazant, M. Z., Sinclair, R. n., Dionne, J. A. 2018; 9 (1): 1775

  Abstract

  Nanorods are promising components of energy and information storage devices that rely on solute-driven phase transformations, due to their large surface-to-volume ratio and ability to accommodate strain. Here we investigate the hydrogen-induced phase transition in individual penta-twinned palladium nanorods of varying aspect ratios with ~3 nm spatial resolution to understand the correlation between nanorod structure and thermodynamics. We find that the hydrogenated phase preferentially nucleates at the rod tips, progressing along the length of the nanorods with increasing hydrogen pressure. While nucleation pressure is nearly constant for all lengths, the number of phase boundaries is length-dependent, with stable phase coexistence always occurring for rods longer than 55 nm. Moreover, such coexistence occurs within individual crystallites of the nanorods and is accompanied by defect formation, as supported by in situ electron microscopy and elastic energy calculations. These results highlight the effect of particle shape and dimension on thermodynamics, informing nanorod design for improved device cyclability.

  View details for PubMedID 29720644

  View details for PubMedCentralID PMC5932065

• Nanoscopic control and quantification of enantioselective optical forces. Nature nanotechnology Zhao, Y., Saleh, A. A., van de Haar, M. A., Baum, B., Briggs, J. A., Lay, A., Reyes-Becerra, O. A., Dionne, J. A. 2017; 12 (11): 1055-1059

  Abstract

  Circularly polarized light (CPL) exerts a force of different magnitude on left- and right-handed enantiomers, an effect that could be exploited for chiral resolution of chemical compounds as well as controlled assembly of chiral nanostructures. However, enantioselective optical forces are challenging to control and quantify because their magnitude is extremely small (sub-piconewton) and varies in space with sub-micrometre resolution. Here, we report a technique to both strengthen and visualize these forces, using a chiral atomic force microscope probe coupled to a plasmonic optical tweezer. Illumination of the plasmonic tweezer with CPL exerts a force on the microscope tip that depends on the handedness of the light and the tip. In particular, for a left-handed chiral tip, transverse forces are attractive with left-CPL and repulsive with right-CPL. Additionally, total force differences between opposite-handed specimens exceed 10 pN. The microscope tip can map chiral forces with 2 nm lateral resolution, revealing a distinct spatial distribution of forces for each handedness.

  View details for DOI 10.1038/nnano.2017.180

  View details for PubMedID 28945237

  View details for PubMedCentralID PMC5679370

• Hot-Carrier-Mediated Photon Upconversion in Metal-Decorated Quantum Wells. Nano letters Naik, G. V., Welch, A. J., Briggs, J. A., Solomon, M. L., Dionne, J. A. 2017; 17 (8): 4583-4587

  Abstract

  Manipulating the frequency of electromagnetic waves forms the core of many modern technologies, ranging from imaging and spectroscopy to radio and optical communication. The process of converting photons from higher to lower energy is easily accomplished and technologically widespread. However, upconversion, which is the process of converting lower-energy photons into higher-energy photons, is still a growing field of study with nascent applications and burgeoning interest. Here, we experimentally demonstrate a new photon upconversion technique mediated by hot carriers in plasmonic nanostructures. Hot holes and hot electrons generated via plasmon decay in illuminated metal nanoparticles are injected into an adjacent semiconductor quantum well where they radiatively recombine to emit higher-energy photons. Using GaN/InGaN quantum wells decorated with gold and silver nanoparticles, we show photon upconversion from 2.4 to 2.8 eV. The process scales linearly with illumination power and enables both geometry- and polarization-based tunability. The conversion of plasmonic losses into upconverted optical emission has the potential to impact bioimaging, on-chip wavelength conversion, and high-efficiency photovoltaics.

  View details for DOI 10.1021/acs.nanolett.7b00900

  View details for PubMedID 28661675

• Temperature-dependent optical properties of titanium nitride APPLIED PHYSICS LETTERS Briggs, J. A., Naik, G. V., Zhao, Y., Petach, T. A., Sahasrabuddhe, K., Goldhaber-Gordon, D., Melosh, N. A., Dionne, J. A. 2017; 110 (10)

  View details for DOI 10.1063/1.4977840

  View details for Web of Science ID 000397871800011

• Enhancing Enantioselective Absorption Using Dielectric Nanospheres ACS PHOTONICS Ho, C., Garcia-Etxarri, A., Zhao, Y., Dionne, J. 2017; 4 (2): 197-203

  View details for DOI 10.1021/acsphotonics.6b00701

  View details for Web of Science ID 000394483500001

• Direct visualization of hydrogen absorption dynamics in individual palladium nanoparticles NATURE COMMUNICATIONS Narayan, T. C., Hayee, F., Baldi, A., Koh, A. L., Sinclair, R., Dionne, J. A. 2017; 8

  View details for DOI 10.1038/ncomms14020

  View details for Web of Science ID 000391869800001

• Direct visualization of hydrogen absorption dynamics in individual palladium nanoparticles. Nature communications Narayan, T. C., Hayee, F., Baldi, A., Leen Koh, A., Sinclair, R., Dionne, J. A. 2017; 8: 14020-?

  Abstract

  Many energy storage materials undergo large volume changes during charging and discharging. The resulting stresses often lead to defect formation in the bulk, but less so in nanosized systems. Here, we capture in real time the mechanism of one such transformation-the hydrogenation of single-crystalline palladium nanocubes from 15 to 80 nm-to better understand the reason for this durability. First, using environmental scanning transmission electron microscopy, we monitor the hydrogen absorption process in real time with 3 nm resolution. Then, using dark-field imaging, we structurally examine the reaction intermediates with 1 nm resolution. The reaction proceeds through nucleation and growth of the new phase in corners of the nanocubes. As the hydrogenated phase propagates across the particles, portions of the lattice misorient by 1.5%, diminishing crystal quality. Once transformed, all the particles explored return to a pristine state. The nanoparticles' ability to remove crystallographic imperfections renders them more durable than their bulk counterparts.

  View details for DOI 10.1038/ncomms14020

  View details for PubMedID 28091597

  View details for PubMedCentralID PMC5241819

• Nanoscopic control and quantification of enantioselective optical forces Nature Nanotechnology Zhao, Y., Saleh, A., van de Haar, M., Baum, B., Briggs, J. A., Lay, A., Reyes-Becerra, O. A., Dionne, J. A. 2017: 1055–59

  Abstract

  Circularly polarized light (CPL) exerts a force of different magnitude on left- and right-handed enantiomers, an effect that could be exploited for chiral resolution of chemical compounds as well as controlled assembly of chiral nanostructures. However, enantioselective optical forces are challenging to control and quantify because their magnitude is extremely small (sub-piconewton) and varies in space with sub-micrometre resolution. Here, we report a technique to both strengthen and visualize these forces, using a chiral atomic force microscope probe coupled to a plasmonic optical tweezer. Illumination of the plasmonic tweezer with CPL exerts a force on the microscope tip that depends on the handedness of the light and the tip. In particular, for a left-handed chiral tip, transverse forces are attractive with left-CPL and repulsive with right-CPL. Additionally, total force differences between opposite-handed specimens exceed 10 pN. The microscope tip can map chiral forces with 2 nm lateral resolution, revealing a distinct spatial distribution of forces for each handedness.

  View details for DOI 10.1038/nnano.2017.180

  View details for PubMedCentralID PMC5679370

• Grating-flanked plasmonic coaxial apertures for efficient fiber optical tweezers. Optics express Saleh, A. A., Sheikhoelislami, S., Gastelum, S., Dionne, J. A. 2016; 24 (18): 20593-20603

  Abstract

  Subwavelength plasmonic apertures have been foundational for direct optical manipulation of nanoscale specimens including sub-100 nm polymeric beads, metallic nanoparticles and proteins. While most plasmonic traps result in two-dimensional localization, three-dimensional manipulation has been demonstrated by integrating a plasmonic aperture on an optical fiber tip. However, such 3D traps are usually inefficient since the optical mode of the fiber and the subwavelength aperture only weakly couple. In this paper we design more efficient optical-fiber-based plasmonic tweezers combining a coaxial plasmonic aperture with a plasmonic grating coupler at the fiber tip facet. Using full-field finite difference time domain analysis, we optimize the grating design for both gold and silver fiber-based coaxial tweezers such that the optical transmission through the apertures is maximized. With the optimized grating, we show that the maximum transmission efficiency increases from 2.5% to 19.6% and from 1.48% to 16.7% for the gold and silver structures respectively. To evaluate their performance as optical tweezers, we calculate the optical forces and the corresponding trapping potential on dielectric particles interacting with the apertures. We demonstrate that the enahncement in the transmission translates into an equivalent increase in the optical forces. Consequently, the optical power required to achieve stable optical trapping is significantly reduced allowing for efficient localization and 3D manipulation of sub-30 nm dielectric particles.

  View details for DOI 10.1364/OE.24.020593

  View details for PubMedID 27607663

• Enhancing Quantum Yield via Local Symmetry Distortion in Lanthanide-Based Upconverting Nanoparticles ACS PHOTONICS Wisser, M. D., Fischer, S., Maurer, P. C., Bronstein, N. D., Chu, S., Alivisatos, A. P., Salleo, A., Dionne, J. A. 2016; 3 (8): 1523-1530

  View details for DOI 10.1021/acsphotonics.6b00166

  View details for Web of Science ID 000381717600023

• Roadmap on optical energy conversion JOURNAL OF OPTICS Boriskina, S. V., Green, M. A., Catchpole, K., Yablonovitch, E., Beard, M. C., Okada, Y., Lany, S., Gershon, T., Zakutayev, A., Tahersima, M. H., Sorger, V. J., Naughton, M. J., Kempa, K., Dagenais, M., Yao, Y., Xu, L., Sheng, X., Bronstein, N. D., Rogers, J. A., Alivisatos, A. P., Nuzzo, R. G., Gordon, J. M., Wu, D. M., Wisser, M. D., Salleo, A., Dionne, J., Bermel, P., Greffet, J., Celanovic, I., Soljacic, M., Manor, A., Rotschild, C., Raman, A., Zhu, L., Fan, S., Chen, G. 2016; 18 (7)

  View details for DOI 10.1088/2040-8978/18/7/073004

  View details for Web of Science ID 000383908800007

• Reconstructing solute-induced phase transformations within individual nanocrystals NATURE MATERIALS Narayan, T. C., Baldi, A., Koh, A. L., Sinclair, R., Dionne, J. A. 2016; 15 (7): 768-?

  Abstract

  Strain and defects can significantly impact the performance of functional nanomaterials. This effect is well exemplified by energy storage systems, in which structural changes such as volume expansion and defect generation govern the phase transformations associated with charging and discharging. The rational design of next-generation storage materials therefore depends crucially on understanding the correlation between the structure of individual nanoparticles and their solute uptake and release. Here, we experimentally reconstruct the spatial distribution of hydride phases within individual palladium nanocrystals during hydrogen absorption, using a combination of electron spectroscopy, dark-field imaging, and electron diffraction in an environmental transmission electron microscope. We show that single-crystalline cubes and pyramids exhibit a uniform hydrogen distribution at equilibrium, whereas multiply twinned icosahedra exclude hydrogen from regions of high compressive strains. Our technique offers unprecedented insight into nanoscale phase transformations in reactive environments and can be extended to a variety of functional nanomaterials.

  View details for DOI 10.1038/NMAT4620

  View details for Web of Science ID 000378347800027

  View details for PubMedID 27088234

• Towards nanoscale multiplexing with parity-time-symmetric plasmonic coaxial waveguides PHYSICAL REVIEW B Alaeian, H., Baum, B., Jankovic, V., Lawrence, M., Dionne, J. A. 2016; 93 (20)

  View details for DOI 10.1103/PhysRevB.93.205439

  View details for Web of Science ID 000376639000005

• Enantioselective Optical Trapping of Chiral Nanoparticles with Plasmonic Tweezers ACS PHOTONICS Zhao, Y., Saleh, A. A., Dionne, J. A. 2016; 3 (3): 304-309

  View details for DOI 10.1021/acsphotonics.5b00574

  View details for Web of Science ID 000372479500001

• Fully CMOS-compatible titanium nitride nanoantennas APPLIED PHYSICS LETTERS Briggs, J. A., Naik, G. V., Petach, T. A., Baum, B. K., Goldhaber-Gordon, D., Dionne, J. A. 2016; 108 (5)

  View details for DOI 10.1063/1.4941413

  View details for Web of Science ID 000373055700010

• Evolution of Plasmonic Metamolecule Modes in the Quantum Tunneling Regime. ACS nano Scholl, J. A., Garcia-Etxarri, A., Aguirregabiria, G., Esteban, R., Narayan, T. C., Koh, A. L., Aizpurua, J., Dionne, J. A. 2016; 10 (1): 1346-1354

  Abstract

  Plasmonic multinanoparticle systems exhibit collective electric and magnetic resonances that are fundamental for the development of state-of-the-art optical nanoantennas, metamaterials, and surface-enhanced spectroscopy substrates. While electric dipolar modes have been investigated in both the classical and quantum realm, little attention has been given to magnetic and other "dark" modes at the smallest dimensions. Here, we study the collective electric, magnetic, and dark modes of colloidally synthesized silver nanosphere trimers with varying interparticle separation using scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). This technique enables direct visualization and spatially selective excitation of individual trimers, as well as manipulation of the interparticle distance into the subnanometer regime with the electron beam. Our experiments reveal that bonding electric and magnetic modes are significantly impacted by quantum effects, exhibiting a relative blueshift and reduced EELS amplitude compared to classical predictions. In contrast, the trimer's electric dark mode is not affected by quantum tunneling for even Ångström-scale interparticle separations. We employ a quantum-corrected model to simulate the effect of electron tunneling in the trimer which shows excellent agreement with experimental results. This understanding of classical and quantum-influenced hybridized modes may impact the development of future quantum plasmonic materials and devices, including Fano-like molecular sensors and quantum metamaterials.

  View details for DOI 10.1021/acsnano.5b06738

  View details for PubMedID 26639023

• Plasmonics feature issue: publisher's note OPTICAL MATERIALS EXPRESS Boltasseva, A., Dionne, J. 2015; 5 (12): 2978-2978

  View details for DOI 10.1364/OME.5.002978

  View details for Web of Science ID 000366045900027

• Localized fields, global impact: Industrial applications of resonant plasmonic materials MRS BULLETIN Dionne, J. A., Baldi, A., Baum, B., Ho, C., Jankovic, V., Naik, G. V., Narayan, T., Scholl, J. A., Zhao, Y. 2015; 40 (12): 1138-1145

  View details for DOI 10.1557/mrs.2015.233

  View details for Web of Science ID 000365744400014

• Feature issue introduction: plasmonics OPTICAL MATERIALS EXPRESS Boltasseva, A., Dionne, J. 2015; 5 (11): 2698-2701

  View details for DOI 10.1364/OME.5.002698

  View details for Web of Science ID 000364467700034

• Photon upconversion with hot carriers in plasmonic systems APPLIED PHYSICS LETTERS Naik, G. V., Dionne, J. A. 2015; 107 (13)

  View details for DOI 10.1063/1.4932127

  View details for Web of Science ID 000362575600051

• Polymer lattices as mechanically tunable 3-dimensional photonic crystals operating in the infrared APPLIED PHYSICS LETTERS Chernow, V. F., Alaeian, H., Dionne, J. A., Greer, J. R. 2015; 107 (10)

  View details for DOI 10.1063/1.4930819

  View details for Web of Science ID 000361640200018

• Controlling electric, magnetic, and chiral dipolar emission with PT-symmetric potentials PHYSICAL REVIEW B Alaeian, H., Dionne, J. A. 2015; 91 (24)

  View details for DOI 10.1103/PhysRevB.91.245108

  View details for Web of Science ID 000355647400003

• Nanoscale optical tomography with cathodoluminescence spectroscopy NATURE NANOTECHNOLOGY Atre, A. C., Brenny, B. J., Coenen, T., Garcia-Etxarri, A., Polman, A., Dionne, J. A. 2015; 10 (5): 429-436

  Abstract

  Tomography has enabled the characterization of the Earth's interior, visualization of the inner workings of the human brain, and three-dimensional reconstruction of matter at the atomic scale. However, tomographic techniques that rely on optical excitation or detection are generally limited in their resolution by diffraction. Here, we introduce a tomographic technique--cathodoluminescence spectroscopic tomography--to probe optical properties in three dimensions with nanometre-scale spatial and spectral resolution. We first obtain two-dimensional cathodoluminescence maps of a three-dimensional nanostructure at various orientations. We then use the method of filtered back-projection to reconstruct the cathodoluminescence intensity at each wavelength. The resulting tomograms allow us to locate regions of efficient cathodoluminescence in three dimensions across visible and near-infrared wavelengths, with contributions from material luminescence and radiative decay of electromagnetic eigenmodes. The experimental signal can be further correlated with the radiative local density of optical states in particular regions of the reconstruction. We demonstrate how cathodoluminescence tomography can be used to achieve nanoscale three-dimensional visualization of light-matter interactions by reconstructing a three-dimensional metal-dielectric nanoresonator.

  View details for DOI 10.1038/NNANO.2015.39

  View details for Web of Science ID 000354094900012

  View details for PubMedID 25849788

• Strain-induced modification of optical selection rules in lanthanide-based upconverting nanoparticles. Nano letters Wisser, M. D., Chea, M., Lin, Y., Wu, D. M., Mao, W. L., Salleo, A., Dionne, J. A. 2015; 15 (3): 1891-1897

  Abstract

  NaYF4:Yb(3+),Er(3+) nanoparticle upconverters are hindered by low quantum efficiencies arising in large part from the parity-forbidden nature of their optical transitions and the nonoptimal spatial separations between lanthanide ions. Here, we use pressure-induced lattice distortion to systematically modify both parameters. Although hexagonal-phase nanoparticles exhibit a monotonic decrease in upconversion emission, cubic-phase particles experience a nearly 2-fold increase in efficiency. In-situ X-ray diffraction indicates that these emission changes require only a 1% reduction in lattice constant. Our work highlights the intricate relationship between upconversion efficiency and lattice geometry and provides a promising approach to modifying the quantum efficiency of any lanthanide upconverter.

  View details for DOI 10.1021/nl504738k

  View details for PubMedID 25647523

• Lights, nano, action! New plasmonic materials and methods to probe nanoscale phenomena MRS BULLETIN Dionne, J. A. 2015; 40 (3): 264-270

  View details for DOI 10.1557/mrs.2015.31

  View details for Web of Science ID 000351157100021

• A parity-time symmetric coherent plasmonic absorber-amplifier JOURNAL OF APPLIED PHYSICS Baum, B., Alaeian, H., Dionne, J. 2015; 117 (6)

  View details for DOI 10.1063/1.4907871

  View details for Web of Science ID 000349846300006

• 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

• Strain-induced modification of optical selection rules in lanthanide-based upconverting nanoparticles Nano Letters Wisser, M., Chea, M., Lin, Y., Wu, D., Mao, W. L., Salleo, A., Dionne, J. 2015: 1891–97

  Abstract

  NaYF4:Yb(3+),Er(3+) nanoparticle upconverters are hindered by low quantum efficiencies arising in large part from the parity-forbidden nature of their optical transitions and the nonoptimal spatial separations between lanthanide ions. Here, we use pressure-induced lattice distortion to systematically modify both parameters. Although hexagonal-phase nanoparticles exhibit a monotonic decrease in upconversion emission, cubic-phase particles experience a nearly 2-fold increase in efficiency. In-situ X-ray diffraction indicates that these emission changes require only a 1% reduction in lattice constant. Our work highlights the intricate relationship between upconversion efficiency and lattice geometry and provides a promising approach to modifying the quantum efficiency of any lanthanide upconverter.

  View details for DOI 10.1021/nl504738k

• Upconversion for Enhanced Photovoltaics 3rd Physics of Sustainable Energy (PSE) Conference Briggs, J. A., Wu, D. M., Atre, A. C., Garcia-Etxarri, A., Dionne, J. A. AMER INST PHYSICS. 2015: 33–43

  View details for DOI 10.1063/1.4916166

  View details for Web of Science ID 000354881700003

• In situ detection of hydrogen-induced phase transitions in individual palladium nanocrystals NATURE MATERIALS Baldi, A., Narayan, T. C., Koh, A. L., Dionne, J. A. 2014; 13 (12): 1143-1148

  View details for DOI 10.1038/NMAT4086

  View details for Web of Science ID 000345432200018

• In situ detection of hydrogen-induced phase transitions in individual palladium nanocrystals. Nature materials Baldi, A., Narayan, T. C., Koh, A. L., Dionne, J. A. 2014; 13 (12): 1143-1148

  Abstract

  Many energy- and information-storage processes rely on phase changes of nanomaterials in reactive environments. Compared to their bulk counterparts, nanostructured materials seem to exhibit faster charging and discharging kinetics, extended life cycles, and size-tunable thermodynamics. However, in ensemble studies of these materials, it is often difficult to discriminate between intrinsic size-dependent properties and effects due to sample size and shape dispersity. Here, we detect the phase transitions of individual palladium nanocrystals during hydrogen absorption and desorption, using in situ electron energy-loss spectroscopy in an environmental transmission electron microscope. In contrast to ensemble measurements, we find that palladium nanocrystals undergo sharp transitions between the α and β phases, and that surface effects dictate the size dependence of the hydrogen absorption pressures. Our results provide a general framework for monitoring phase transitions in individual nanocrystals in a reactive environment and highlight the importance of single-particle approaches for the characterization of nanostructured materials.

  View details for DOI 10.1038/nmat4086

  View details for PubMedID 25194700

• Plasmon-Enhanced Upconversion JOURNAL OF PHYSICAL CHEMISTRY LETTERS Wu, D. M., Garcia-Etxarri, A., Salleo, A., Dionne, J. A. 2014; 5 (22): 4020-4031

  Abstract

  Upconversion, the conversion of photons from lower to higher energies, is a process that promises applications ranging from high-efficiency photovoltaic and photocatalytic cells to background-free bioimaging and therapeutic probes. Existing upconverting materials, however, remain too inefficient for viable implementation. In this Perspective, we describe the significant improvements in upconversion efficiency that can be achieved using plasmon resonances. As collective oscillations of free electrons, plasmon resonances can be used to enhance both the incident electromagnetic field intensity and the radiative emission rates. To date, this approach has shown upconversion enhancements up to 450×. We discuss both theoretical underpinnings and experimental demonstrations of plasmon-enhanced upconversion, examining the roles of upconverter quantum yield, plasmonic geometry, and plasmon spectral overlap. We also discuss nonoptical consequences of including metal nanostructures near upconverting emitters. The rapidly expanding field of plasmon-enhanced upconversion provides novel fundamental insight into nanoscale light-matter interactions while improving prospects for technological relevance.

  View details for DOI 10.1021/jz5019042

  View details for Web of Science ID 000345542900014

• Plasmon-Enhanced Upconversion. journal of physical chemistry letters Wu, D. M., García-Etxarri, A., Salleo, A., Dionne, J. A. 2014; 5 (22): 4020-4031

  Abstract

  Upconversion, the conversion of photons from lower to higher energies, is a process that promises applications ranging from high-efficiency photovoltaic and photocatalytic cells to background-free bioimaging and therapeutic probes. Existing upconverting materials, however, remain too inefficient for viable implementation. In this Perspective, we describe the significant improvements in upconversion efficiency that can be achieved using plasmon resonances. As collective oscillations of free electrons, plasmon resonances can be used to enhance both the incident electromagnetic field intensity and the radiative emission rates. To date, this approach has shown upconversion enhancements up to 450×. We discuss both theoretical underpinnings and experimental demonstrations of plasmon-enhanced upconversion, examining the roles of upconverter quantum yield, plasmonic geometry, and plasmon spectral overlap. We also discuss nonoptical consequences of including metal nanostructures near upconverting emitters. The rapidly expanding field of plasmon-enhanced upconversion provides novel fundamental insight into nanoscale light-matter interactions while improving prospects for technological relevance.

  View details for DOI 10.1021/jz5019042

  View details for PubMedID 26276488

• Parity-time-symmetric plasmonic metamaterials PHYSICAL REVIEW A Alaeian, H., Dionne, J. A. 2014; 89 (3)

  View details for DOI 10.1103/PhysRevA.89.033829

  View details for Web of Science ID 000333184400011

• Non-Hermitian nanophotonic and plasmonic waveguides PHYSICAL REVIEW B Alaeian, H., Dionne, J. A. 2014; 89 (7)

  View details for DOI 10.1103/PhysRevB.89.075136

  View details for Web of Science ID 000332419900002

• A metafluid exhibiting strong optical magnetism. Nano letters Sheikholeslami, S. N., Alaeian, H., Koh, A. L., Dionne, J. A. 2013; 13 (9): 4137-4141

  Abstract

  Advances in the field of metamaterials have enabled unprecedented control of light-matter interactions. Metamaterial constituents support high-frequency electric and magnetic dipoles, which can be used as building blocks for new materials capable of negative refraction, electromagnetic cloaking, strong visible-frequency circular dichroism, and enhancing magnetic or chiral transitions in ions and molecules. While all metamaterials to date have existed in the solid-state, considerable interest has emerged in designing a colloidal metamaterial or "metafluid". Such metafluids would combine the advantages of solution-based processing with facile integration into conventional optical components. Here we demonstrate the colloidal synthesis of an isotropic metafluid that exhibits a strong magnetic response at visible frequencies. Protein-antibody interactions are used to direct the solution-phase self-assembly of discrete metamolecules comprised of silver nanoparticles tightly packed around a single dielectric core. The electric and magnetic response of individual metamolecules and the bulk metamaterial solution are directly probed with optical scattering and spectroscopy. Effective medium calculations indicate that the bulk metamaterial exhibits a negative effective permeability and a negative refractive index at modest fill factors. This metafluid can be synthesized in large-quantity and high-quality and may accelerate development of advanced nanophotonic and metamaterial devices.

  View details for DOI 10.1021/nl401642z

  View details for PubMedID 23919764

• Surface-enhanced circular dichroism spectroscopy mediated by nonchiral nanoantennas PHYSICAL REVIEW B Garcia-Etxarri, A., Dionne, J. A. 2013; 87 (23)

  View details for DOI 10.1103/PhysRevB.87.235409

  View details for Web of Science ID 000320164900008

• NANOPLASMONICS Plasmons rock in metal bands NATURE MATERIALS Dionne, J. A. 2013; 12 (5): 380-381

  View details for DOI 10.1038/nmat3607

  View details for Web of Science ID 000317954800003

  View details for PubMedID 23503013

• A Broadband Negative Index Metamaterial at Optical Frequencies ADVANCED OPTICAL MATERIALS Atre, A. C., Garcia-Etxarri, A., Alaeian, H., Dionne, J. A. 2013; 1 (4): 327-333

  View details for DOI 10.1002/adom.201200022

  View details for Web of Science ID 000320998600009

• Narrow-bandwidth solar upconversion: Case studies of existing systems and generalized fundamental limits JOURNAL OF APPLIED PHYSICS Briggs, J. A., Atre, A. C., Dionne, J. A. 2013; 113 (12)

  View details for DOI 10.1063/1.4796092

  View details for Web of Science ID 000316967800061

• Observation of Quantum Tunneling between Two Plasmonic Nanoparticles NANO LETTERS Scholl, J. A., Garcia-Etxarri, A., Koh, A. L., Dionne, J. A. 2013; 13 (2): 564-569

  Abstract

  The plasmon resonances of two closely spaced metallic particles have enabled applications including single-molecule sensing and spectroscopy, novel nanoantennas, molecular rulers, and nonlinear optical devices. In a classical electrodynamic context, the strength of such dimer plasmon resonances increases monotonically as the particle gap size decreases. In contrast, a quantum mechanical framework predicts that electron tunneling will strongly diminish the dimer plasmon strength for subnanometer-scale separations. Here, we directly observe the plasmon resonances of coupled metallic nanoparticles as their gap size is reduced to atomic dimensions. Using the electron beam of a scanning transmission electron microscope (STEM), we manipulate pairs of ~10-nm-diameter spherical silver nanoparticles on a substrate, controlling their convergence and eventual coalescence into a single nanosphere. We simultaneously employ electron energy-loss spectroscopy (EELS) to observe the dynamic plasmonic properties of these dimers before and after particle contact. As separations are reduced from 7 nm, the dominant dipolar peak exhibits a redshift consistent with classical calculations. However, gaps smaller than ~0.5 nm cause this mode to exhibit a reduced intensity consistent with quantum theories that incorporate electron tunneling. As the particles overlap, the bonding dipolar mode disappears and is replaced by a dipolar charge transfer mode. Our dynamic imaging, manipulation, and spectroscopy of nanostructures enables the first full spectral mapping of dimer plasmon evolution and may provide new avenues for in situ nanoassembly and analysis in the quantum regime.

  View details for DOI 10.1021/nl304078v

  View details for Web of Science ID 000315079500040

  View details for PubMedID 23245286

• Plasmons rock in metal bands Nature Materials 12 Dionne, J. 2013: 380
• Toward Efficient Optical Trapping of Sub-10-nm Particles with Coaxial Plasmonic Apertures NANO LETTERS Saleh, A. A., Dionne, J. A. 2012; 12 (11): 5581-5586

  Abstract

  Optical trapping using focused laser beams has emerged as a powerful tool in the biological and physical sciences. However, scaling this technique to nanosized objects remains challenging due to the diffraction limit of light and the high power levels required for nanoscale trapping. In this paper, we propose plasmonic coaxial apertures as low-power optical traps for nanosized specimens. The illumination of a coaxial aperture with a linearly polarized plane wave generates a dual optical trapping potential well. We theoretically show that this potential can stably trap dielectric particles smaller than 10 nm in diameter while keeping the trapping power level below 20 mW. By tapering the thickness of the coaxial dielectric channel, trapping can be extended to sub-2-nm particles. The proposed structures may enable optical trapping and manipulation of dielectric particles ranging from single proteins to small molecules with sizes previously inaccessible.

  View details for DOI 10.1021/nl302627c

  View details for Web of Science ID 000311244400023

  View details for PubMedID 23035765

• Plasmonics: Metal-worthy methods and materials in nanophotonics MRS BULLETIN Dionne, J. A., Atwater, H. A. 2012; 37 (8): 717-724

  View details for DOI 10.1557/mrs.2012.171

  View details for Web of Science ID 000308083700008

• Plasmon nanoparticle superlattices as optical-frequency magnetic metamaterials OPTICS EXPRESS Alaeian, H., Dionne, J. A. 2012; 20 (14): 15781-15796

  Abstract

  Nanocrystal superlattices have emerged as a new platform for bottom-up metamaterial design, but their optical properties are largely unknown. Here, we investigate their emergent optical properties using a generalized semi-analytic, full-field solver based on rigorous coupled wave analysis. Attention is given to superlattices composed of noble metal and dielectric nanoparticles in unary and binary arrays. By varying the nanoparticle size, shape, separation, and lattice geometry, we demonstrate the broad tunability of superlattice optical properties. Superlattices composed of spherical or octahedral nanoparticles in cubic and AB(2) arrays exhibit magnetic permeabilities tunable between 0.2 and 1.7, despite having non-magnetic constituents. The retrieved optical parameters are nearly polarization and angle-independent over a broad range of incident angles. Accordingly, nanocrystal superlattices behave as isotropic bulk metamaterials. Their tunable permittivities, permeabilities, and emergent magnetism may enable new, bottom-up metamaterials and negative index materials at visible frequencies.

  View details for Web of Science ID 000306176100110

  View details for PubMedID 22772268

• Opportunities and Challenges of Using Plasmonic Components in Nanophotonic Architectures IEEE JOURNAL ON EMERGING AND SELECTED TOPICS IN CIRCUITS AND SYSTEMS Wassel, H. M., Dai, D., Tiwari, M., Valamehr, J. K., Theogarajan, L., Dionne, J., Chong, F. T., Sherwood, T. 2012; 2 (2): 154-168

  View details for DOI 10.1109/JETCAS.2012.2193934

  View details for Web of Science ID 000208972800004

• Quantum plasmon resonances of individual metallic nanoparticles NATURE Scholl, J. A., Koh, A. L., Dionne, J. A. 2012; 483 (7390): 421-U68

  Abstract

  The plasmon resonances of metallic nanoparticles have received considerable attention for their applications in nanophotonics, biology, sensing, spectroscopy and solar energy harvesting. Although thoroughly characterized for spheres larger than ten nanometres in diameter, the plasmonic properties of particles in the quantum size regime have been historically difficult to describe owing to weak optical scattering, metal-ligand interactions, and inhomogeneity in ensemble measurements. Such difficulties have precluded probing and controlling the plasmonic properties of quantum-sized particles in many natural and engineered processes, notably catalysis. Here we investigate the plasmon resonances of individual ligand-free silver nanoparticles using aberration-corrected transmission electron microscope (TEM) imaging and monochromated scanning TEM electron energy-loss spectroscopy (EELS). This technique allows direct correlation between a particle's geometry and its plasmon resonance. As the nanoparticle diameter decreases from 20 nanometres to less than two nanometres, the plasmon resonance shifts to higher energy by 0.5 electronvolts, a substantial deviation from classical predictions. We present an analytical quantum mechanical model that describes this shift due to a change in particle permittivity. Our results highlight the quantum plasmonic properties of small metallic nanospheres, with direct application to understanding and exploiting catalytically active and biologically relevant nanoparticles.

  View details for DOI 10.1038/nature10904

  View details for Web of Science ID 000301771200034

  View details for PubMedID 22437611

• Toward high-efficiency solar upconversion with plasmonic nanostructures JOURNAL OF OPTICS Atre, A. C., Garcia-Etxarri, A., Alaeian, H., Dionne, J. A. 2012; 14 (2)

  View details for DOI 10.1088/2040-8978/14/2/024008

  View details for Web of Science ID 000300303400009

• Optimized light absorption in Si wire array solar cells JOURNAL OF OPTICS Alaeian, H., Atre, A. C., Dionne, J. A. 2012; 14 (2)

  View details for DOI 10.1088/2040-8978/14/2/024006

  View details for Web of Science ID 000300303400007

• Waveguides with a silver lining: Low threshold gain and giant modal gain in active cylindrical and coaxial plasmonic devices PHYSICAL REVIEW B Saleh, A. A., Dionne, J. A. 2012; 85 (4)

  View details for DOI 10.1103/PhysRevB.85.045407

  View details for Web of Science ID 000298865200008

• Mirror, Mirror Physics 5 Dionne, J. 2012: 38
• Controlling the Interplay of Electric and Magnetic Modes via Fano-like Plasmon Resonances NANO LETTERS Sheikholeslami, S. N., Garcia-Etxarri, A., Dionne, J. A. 2011; 11 (9): 3927-3934

  Abstract

  Assemblies of strongly coupled plasmonic nanoparticles can support highly tunable electric and magnetic resonances in the visible spectrum. In this Letter, we theoretically demonstrate Fano-like interference effects between the fields radiated by the electric and magnetic modes of symmetric nanoparticle trimers. Breaking the symmetry of the trimer system leads to a strong interaction between the modes. The near and far-field electromagnetic properties of the broken symmetry trimer are tunable across a large spectral range. We exploit this Fano-like effect to demonstrate spatial and temporal control of the localized electromagnetic hotspots in the plasmonic trimer.

  View details for DOI 10.1021/nl202143j

  View details for Web of Science ID 000294790200072

  View details for PubMedID 21819059

• Realistic upconverter-enhanced solar cells with non-ideal absorption and recombination efficiencies JOURNAL OF APPLIED PHYSICS Atre, A. C., Dionne, J. A. 2011; 110 (3)

  View details for DOI 10.1063/1.3610522

  View details for Web of Science ID 000293956600144

• Giving photovoltaics the green light: Plasmon-enhanced upconversion for broadband solar absorption IEEE Photonics Conference (PHO) Dionne, J. A., Atre, A., Alaeian, H., Garcia, A. IEEE. 2011: 447–448

  View details for Web of Science ID 000299750700224

• Observations of shape-dependent hydrogen uptake trajectories from single nanocrystals JACS Communications Tang, M., L., Liu, N., Dionne, J., Alivisatos, A., P. 2011
• Si-based plasmonics for on-chip photonics invited review, Journal of Selected Topics in Quantum Electronics Dionne, J., Sweatlock, L., Sheldon, M., Alivisatos, A., P., Atwater, H. 2010; 16: 295
• Tunable color filters based on metal-insulator-metal resonators Nano Letters 9 Diest, K., Dionne, J., Spain, M., Atwater, H. 2009: 2579
• Flatland Photonics: Circumventing diffraction with planar plasmonic architectures Caltech Thesis Dionne, J. 2009
• PlasMOStor: a metal-oxide-silicon field-effect plasmonic modulator Nano Letters 9 Dionne, J., Diest, K., Sweatlock, L., Atwater, H. 2009: 897
• Are negative index materials achievable with surface plasmon waveguides? A case study of three plasmonic geometries Optics Express 16 Dionne, J., Verhagen, E., Polman, A., Atwater, H. 2008: 19001
• Near field visualization of strongly confined surface plasmon polaritons in metal-insulator-metal waveguides Nano Letters 8 Verhagen, E., Dionne, J., Kuipers, K., Atwater, H., Polman, A. 2008: 2925
• Silver diffusion bonding and layer transfer of lithium niobate to silver Applied Physics Letters 93 Diest, K., Archer, M., Dionne, J., Czubakowski, M., Atwater, H. 2008: 092906
• Negative refraction at visible frequencies Science 316 Lezec, H., Dionne, J., Atwater, H. 2007: 430
• Highly confined photon transport in subwavelength metallic slot waveguides NanoLetters 6 Dionne, J., Lezec, H., Atwater, H. 2006: 1928
• Plasmon slot waveguides: Towards chip-scale propagation with subwavelenth-scale localization Phys. Rev. B 73 Dionne, J., Sweatlock, L., Polman, A., Atwater, H. 2006: 035407
• Planar metal plasmon waveguides: frequency-dependent dispersion, propagation, localization, and loss beyond the free electron model Phys. Rev. B 72 Dionne, J., Sweatlock, L., Polman, A., Atwater, H. 2005: 075405
• The new ‘PN junction’: Plasmonics enables photonic access to the nanoworld MRS Bulletin Atwater, H., Maier, S., Polman, A., Dionne, J., Sweatlock, L. 2005: 30
• Subwavelength-scale plasmon waveguides Surface Plasmon Photonics Atwater, H., Dionne, J., Sweatlock, L. edited by Brongersma, M., L., Kik, P., G. Dordrecht, NL: Springer. : 87–104