103 results match your criteria Acs Photonics[Journal]


Relevance of the Quadratic Diamagnetic and Self-Polarization Terms in Cavity Quantum Electrodynamics.

ACS Photonics 2020 Apr 26;7(4):975-990. Epub 2020 Feb 26.

Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science & Department of Physics, Luruper Chaussee 149, 22761 Hamburg, Germany.

Experiments at the interface of quantum optics and chemistry have revealed that strong coupling between light and matter can substantially modify the chemical and physical properties of molecules and solids. While the theoretical description of such situations is usually based on nonrelativistic quantum electrodynamics, which contains quadratic light-matter coupling terms, it is commonplace to disregard these terms and restrict the treatment to purely bilinear couplings. In this work, we clarify the physical origin and the substantial impact of the most common quadratic terms, the diamagnetic and self-polarization terms, and highlight why neglecting them can lead to rather unphysical results. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7164385PMC

A Direct Epitaxial Approach To Achieving Ultrasmall and Ultrabright InGaN Micro Light-Emitting Diodes (μLEDs).

ACS Photonics 2020 Feb 10;7(2):411-415. Epub 2020 Jan 10.

Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom.

A direct epitaxial approach to achieving ultrasmall and ultrabright InGaN micro light-emitting diodes (μLEDs) has been developed, leading to the demonstration of . The approach does not involve any dry-etching processes which are exclusively used by any current μLED fabrication approaches. As a result, our approach has entirely eliminated any damage induced during the dry-etching processes. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147254PMC
February 2020

Low-Cost RoHS Compliant Solution Processed Photovoltaics Enabled by Ambient Condition Synthesis of AgBiS Nanocrystals.

ACS Photonics 2020 Mar 4;7(3):588-595. Epub 2020 Mar 4.

ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.

Two major challenges exist before colloidal nanocrystal solar cells can take their place in the market: So far, these devices are based on Pb/Cd-containing nanocrystals, and second, the synthesis of these nanocrystals takes place in an inert atmosphere at elevated temperatures due to the use of air-sensitive chemicals. In this report, a room-temperature, ambient-air synthesis for nontoxic AgBiS nanocrystals is presented. As this method utilizes stable precursors, the need for the use of a protective environment is eliminated, enabling the large-scale production of AgBiS nanocrystals. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7082833PMC

Quantitative Measurement of the Optical Cross Sections of Single Nano-objects by Correlative Transmission and Scattering Microspectroscopy.

ACS Photonics 2019 Aug 21;6(8):2149-2160. Epub 2019 Jul 21.

Cardiff University, School of Biosciences, Museum Avenue, Cardiff CF10 3AX, U.K.

The scattering and absorption of light by nano-objects is a key physical property exploited in many applications, including biosensing and photovoltaics. Yet, its quantification at the single object level is challenging and often requires expensive and complicated techniques. We report a method based on a commercial transmission microscope to measure the optical scattering and absorption cross sections of individual nano-objects. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00727DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011706PMC

Formation Rules and Dynamics of Photoinduced χ Gratings in Silicon Nitride Waveguides.

ACS Photonics 2020 Jan 9;7(1):147-153. Epub 2019 Dec 9.

Ecole Polytechnique Fédérale de Lausanne, Photonic Systems Laboratory (PHOSL), STI-IEL, Station 11, CH-1015 Lausanne, Switzerland.

Silicon nitride has emerged as a prominent platform for building photonics integrated circuits. While its nonlinear properties based on third-order effects have been successfully exploited, an efficient second harmonic generation in standard stoichiometric silicon nitride (SiN) waveguides can also be achieved after all-optical poling, as was recently shown. The root of such a phenomenon has been attributed to the inscription of a self-organized periodic space-charge grating along the waveguide, allowing an effective χ and automatic quasi-phase-matching of pump and second harmonic. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996647PMC
January 2020

GaAs Quantum Dot in a Parabolic Microcavity Tuned to Rb D.

ACS Photonics 2020 Jan 19;7(1):29-35. Epub 2019 Dec 19.

Department of Applied Physics, Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.

We develop a structure to efficiently extract photons emitted by a GaAs quantum dot tuned to rubidium. For this, we employ a broadband microcavity with a curved gold backside mirror that we fabricate by a combination of photoresist reflow, dry reactive ion etching in an inductively coupled plasma, and selective wet chemical etching. Precise reflow and etching control allows us to achieve a parabolic backside mirror with a short focal distance of 265 nm. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6994066PMC
January 2020

Electron-Induced State Conversion in Diamond NV Centers Measured with Pump-Probe Cathodoluminescence Spectroscopy.

ACS Photonics 2020 Jan 2;7(1):232-240. Epub 2019 Dec 2.

Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands.

Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications in quantum technologies and metrology. Two charge states are known for NV centers, NV and NV, with the latter being mostly studied due to its long electron spin coherence time. Therefore, control over the charge state of the NV centers is essential. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6967233PMC
January 2020

Grayscale-to-Color: Scalable Fabrication of Custom Multispectral Filter Arrays.

ACS Photonics 2019 Dec 23;6(12):3132-3141. Epub 2019 Oct 23.

Department of Physics, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, U.K.

Snapshot multispectral image (MSI) sensors have been proposed as a key enabler for a plethora of multispectral imaging applications, from diagnostic medical imaging to remote sensing. With each application requiring a different set, and number, of spectral bands, the absence of a scalable, cost-effective manufacturing solution for custom multispectral filter arrays (MSFAs) has prevented widespread MSI adoption. Despite recent nanophotonic-based efforts, such as plasmonic or high-index metasurface arrays, large-area MSFA manufacturing still consists of many-layer dielectric (Fabry-Perot) stacks, requiring separate complex lithography steps for each spectral band and multiple material compositions for each. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6943817PMC
December 2019

Metamaterial Analogues of Molecular Aggregates.

ACS Photonics 2019 Nov 25;6(11):3003-3009. Epub 2019 Oct 25.

Department of Physics and Astronomy, University of Exeter, Exeter, EX44QL, United Kingdom.

Molecular aggregates are a fascinating and important class of materials, particularly in the context of optical (pigmented) materials. In nature, molecular aggregates are employed in photosynthetic light harvesting structures, while synthetic aggregates are employed in new generation molecular sensors and magnets. The roles of disorder and symmetry are vital in determining the photophysical properties of molecular aggregates, but have been hard to investigate experimentally, owing to a lack of sufficient structural control at the molecular level and the challenge of probing their optical response with molecular spatial resolution. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01208DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875897PMC
November 2019

Light-Matter Response in Nonrelativistic Quantum Electrodynamics.

ACS Photonics 2019 Nov 2;6(11):2757-2778. Epub 2019 Oct 2.

Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science and Department of Physics, Luruper Chaussee 149, 22761 Hamburg, Germany.

We derive the full linear-response theory for nonrelativistic quantum electrodynamics in the long wavelength limit and provide a practical framework to solve the resulting equations by using quantum-electrodynamical density-functional theory. We highlight how the coupling between quantized light and matter changes the usual response functions and introduces cross-correlated light-matter response functions. These cross-correlation responses lead to measurable changes in Maxwell's equations due to the quantum-matter-mediated photon-photon interactions. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00768DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875898PMC
November 2019

Reduced Density-Matrix Approach to Strong Matter-Photon Interaction.

ACS Photonics 2019 Nov 5;6(11):2694-2711. Epub 2019 Sep 5.

Theory Department, Max Planck Institute for the Structure and Dynamics of Matter - Luruper Chaussee 149, 22761 Hamburg, Germany.

We present a first-principles approach to electronic many-body systems strongly coupled to cavity modes in terms of matter-photon one-body reduced density matrices. The theory is fundamentally nonperturbative and thus captures not only the effects of correlated electronic systems but accounts also for strong interactions between matter and photon degrees of freedom. We do so by introducing a higher-dimensional auxiliary system that maps the coupled fermion-boson system to a dressed fermionic problem. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875895PMC
November 2019

Converting an Organic Light-Emitting Diode from Blue to White with Bragg Modes.

ACS Photonics 2019 Nov 8;6(11):2655-2662. Epub 2019 Oct 8.

COMP Centre of Excellence, Department of Applied Physics, Aalto University School of Science, FI-00076 Aalto, Finland.

Organic light-emitting diodes (OLEDs) have been established as versatile light sources that allow for easy integration in large-area surfaces and flexible substrates. In addition, the low fabrication cost of OLEDs renders them particularly attractive as general lighting sources. Current methods for the fabrication of white-light OLEDs rely on the combination of multiple organic emitters and/or the incorporation of multiple cavity modes in a thick active medium. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b01206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875896PMC
November 2019

Far-Field Radiation of Three-Dimensional Plasmonic Gold Tapers near Apexes.

ACS Photonics 2019 Oct 17;6(10):2509-2516. Epub 2019 Sep 17.

Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.

Three-dimensional plasmonic gold tapers are widely used structures in nano-optics for achieving imaging at the nanometer scale, enhanced spectroscopy, confined light sources, and ultrafast photoelectron emission. To understand their radiation properties further, especially in the proximity of the apex at the nanoscale, we employ cathodoluminescence spectroscopy with high spatial and energy resolution. The plasmon-induced radiation in the visible spectral range from three-dimensional gold tapers with opening angles of 13° and 47° is investigated under local electron excitation. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6804427PMC
October 2019

Position- and Polarization-Specific Waveguiding of Multi-Emissions in Single ZnO Nanorods.

ACS Photonics 2019 ;6

Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899.

We examine multiphoton-produced optical signals waveguided through single ZnO nanorods (NRs) using a newly developed, scanning offset-emission hyperspectral microscopy (SOHM) technique. Specifically, we concurrently analyze waveguiding behaviors of sum-frequency generation (SFG), deep-trap emissions (DTE), and coherent anti-Stokes Raman scattering (CARS) occurring in individual ZnO NRs. SOHM acquires spectrally-indexed and spatially-resolved intensity maps/spectra of waveguided light intensity while excitation/emission collection positions and light polarization are scanned. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774195PMC
January 2019

Radiation of Dynamic Toroidal Moments.

ACS Photonics 2019 Feb 24;6(2):467-474. Epub 2019 Jan 24.

Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569, Germany.

Dynamic toroidal dipoles, a distinguished class of fundamental electromagnetic sources, receive increasing interest and participate in fascinating electrodynamic phenomena and sensing applications. As described in the literature, the radiative nature of dynamic toroidal dipoles is sometimes confounded, intermixing with static toroidal dipoles and plasmonic dark modes. Here, we elucidate this issue and provide proof-of-principle experiments exclusively on the radiation behavior of dynamic toroidal moments. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01422DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6735299PMC
February 2019

Vibrational Strong Coupling with Surface Plasmons and the Presence of Surface Plasmon Stop Bands.

ACS Photonics 2019 Aug 11;6(8):2110-2116. Epub 2019 Jul 11.

College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, U.K.

We demonstrate strong coupling between surface plasmon resonances and molecular vibrational resonances of poly(methyl methacrylate) (PMMA) molecules in the mid-infrared range through the use of grating coupling, complimenting earlier work using microcavities and localized plasmon resonances. We choose the period of the grating so that we may observe strong coupling between the surface plasmon mode associated with a patterned gold film and the C=O vibrational resonance in an overlying polymer film. We present results from experiments and numerical simulations to show that surface plasmon modes provide convenient open cavities for vibrational strong coupling experiments. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00662DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6711361PMC

Generalized Brewster Angle Effect in Thin-Film Optical Absorbers and Its Application for Graphene Hydrogen Sensing.

ACS Photonics 2019 Jul 18;6(7):1610-1617. Epub 2019 Jun 18.

Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371.

The generalized Brewster angle (GBA) is the incidence angle at polarization by reflection for p- or s-polarized light. Realizing an s-polarization Brewster effect requires a material with magnetic response, which is challenging at optical frequencies since the magnetic response of materials at these frequencies is extremely weak. Here, we experimentally realize the GBA effect in the visible using a thin-film absorber system consisting of a dielectric film on an absorbing substrate. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6646958PMC
July 2019
1 Read

Single-Crystal Rutile TiO Nanocylinders are Highly Effective Transducers of Optical Force and Torque.

ACS Photonics 2019 May 22;6(5):1255-1265. Epub 2019 Apr 22.

Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, The Netherlands.

Optical trapping of (sub)micron-sized particles is broadly employed in nanoscience and engineering. The materials commonly employed for these particles, however, have physical properties that limit the transfer of linear or angular momentum (or both). This reduces the magnitude of forces and torques, and the spatiotemporal resolution, achievable in linear and angular traps. Read More

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http://dx.doi.org/10.1021/acsphotonics.9b00220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524961PMC
May 2019
17 Reads

Visualizing Spatiotemporal Dynamics of Intercellular Mechanotransmission upon Wounding.

ACS Photonics 2018 Sep 20;5(9):3565-3574. Epub 2018 Aug 20.

Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States.

During cell-to-cell communications, the interplay between physical and biochemical cues is essential for informational exchange and functional coordination, especially in multicellular organisms. However, it remains a challenge to visualize intercellular signaling dynamics in single live cells. Here, we report a photonic approach, based on laser microscissors and Förster resonance energy transfer (FRET) microscopy, to study intercellular signaling transmission. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6502247PMC
September 2018
4 Reads

Tamm Plasmons Directionally Enhance Rare-Earth Nanophosphor Emission.

ACS Photonics 2019 Mar 14;6(3):634-641. Epub 2019 Feb 14.

Institute of Materials Science of Seville, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla (US), Américo Vespucio 49, 41092, Seville, Spain.

Rare-earth-based phosphors are the materials on which current solid-state lighting technology is built. However, their large crystal size impedes the tuning, optimization, or manipulation of emitted light that can be achieved by their integration in nanophotonic architectures. Herein we demonstrate a hybrid plasmonic-photonic architecture capable of both channeling in a specific direction and enhancing by eight times the emission radiated by a macroscopically wide layer of nanophosphors. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6488127PMC
March 2019
2 Reads

Barrier Height Tuning of Terahertz Quantum Cascade Lasers for High-Temperature Operation.

ACS Photonics 2018 Nov 17;5(11):4687-4693. Epub 2018 Oct 17.

Photonics Institut, TU Wien, 1040 Vienna, Austria.

Terahertz quantum cascade lasers (QCLs) are excellent coherent light sources, but are still limited to an operating temperature below 200 K. To tackle this, we analyze the influence of the barrier height for the identical three-well terahertz QCL layer sequence by comparing different aluminum concentrations ( = 0.12-0. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6482977PMC
November 2018
3 Reads

Combined Metagratings for Efficient Broad-Angle Scattering Metasurface.

ACS Photonics 2019 Apr 18;6(4):1010-1017. Epub 2019 Mar 18.

Center for Nanophotonics, AMOLF, 1098 XG Amsterdam, The Netherlands.

Spectrally controlled diffusion and reflection of light are key operations for light management in many optical devices. Integration of this operation in complex nanophotonic devices requires a 2D interface that provides tailored spectrum and directivity control. Here, we present a metagrating superstructure that realizes a resonant light reflector with tailored angular scattering profile. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01795DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477802PMC
April 2019
3 Reads

Spatial Resolution of Coherent Cathodoluminescence Super-Resolution Microscopy.

ACS Photonics 2019 Apr 26;6(4):1067-1072. Epub 2019 Feb 26.

Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.

We investigate the nanoscale excitation of Ag nanocubes with coherent cathodoluminescence imaging spectroscopy (CL) to resolve the factors that determine the spatial resolution of CL as a deep-subwavelength imaging technique. The 10-30 keV electron beam coherently excites localized plasmons in 70 nm Ag cubes at 2.4 and 3. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.9b00164
Publisher Site
http://dx.doi.org/10.1021/acsphotonics.9b00164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473507PMC
April 2019
13 Reads

Experimental Demonstration of Ultrafast THz Modulation in a Graphene-Based Thin Film Absorber through Negative Photoinduced Conductivity.

ACS Photonics 2019 Mar 14;6(3):720-727. Epub 2019 Feb 14.

Institute of Electronic Structure and Laser, FORTH, 70013 Heraklion, Crete, Greece.

We present an experimental demonstration and interpretation of an ultrafast optically tunable, graphene-based thin film absorption modulator for operation in the THz regime. The graphene-based component consists of a uniform CVD-grown graphene sheet stacked on an SU-8 dielectric substrate that is grounded by a metallic ground plate. The structure shows enhanced absorption originating from constructive interference of the impinging and reflected waves at the absorbing graphene sheet. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b01595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429433PMC
March 2019
3 Reads

Nanoimaging and Control of Molecular Vibrations through Electromagnetically Induced Scattering Reaching the Strong Coupling Regime.

ACS Photonics 2018 Sep 6;5(9):3594-3600. Epub 2018 Aug 6.

Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, United States.

Optical resonators can enhance light-matter interaction, modify intrinsic molecular properties such as radiative emission rates, and create new molecule-photon hybrid quantum states. To date, corresponding implementations are based on electronic transitions in the visible spectral region with large transition dipoles yet hampered by fast femtosecond electronic dephasing. In contrast, coupling molecular vibrations with their weaker dipoles to infrared optical resonators has been less explored, despite long-lived coherences with 2 orders of magnitude longer dephasing times. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00425DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390704PMC
September 2018
17 Reads

Quantifying the Limits of Detection of Surface-Enhanced Infrared Spectroscopy with Grating Order-Coupled Nanogap Antennas.

ACS Photonics 2018 Oct 10;5(10):4117-4124. Epub 2018 Sep 10.

Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.

Infrared spectroscopy is widely used for biomolecular studies, but struggles when investigating minute quantities of analytes due to the mismatch between vibrational cross sections and IR wavelengths. It is therefore beneficial to enhance absorption signals by confining the infrared light to deeply subwavelength volumes comparable in size to the biomolecules of interest. This can be achieved with surface-enhanced infrared absorption spectroscopy, for which plasmonic nanorod antennas represent the predominant implementation. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390698PMC
October 2018
2 Reads

High Internal Quantum Efficiency Ultraviolet Emission from Phase-Transition Cubic GaN Integrated on Nanopatterned Si(100).

ACS Photonics 2018 8;5(3):955-963. Epub 2018 Jan 8.

Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.

Ultraviolet emission characteristics of cubic (c-) GaN enabled through hexagonal-to-cubic phase transition are reported. Substrate patterning and material growth are shown to affect phase purity and emission characteristics of c-GaN as studied by electron backscatter diffraction, and photo- and cathodoluminescence, respectively. Raman study shows a tensile strain in the c-GaN. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.7b01231
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http://dx.doi.org/10.1021/acsphotonics.7b01231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376204PMC
January 2018
25 Reads

Plasmonic Dispersion Relations and Intensity Enhancement of Metal-Insulator-Metal Nanodisks.

ACS Photonics 2018 Dec 13;5(12):4823-4827. Epub 2018 Nov 13.

Institute of Physics, University of Graz, 8010 Graz, Austria.

We show that the plasmon modes of vertically stacked Ag-SiO-Ag nanodisks can be understood and classified as hybridized surface and edge modes. We describe their universal dispersion relations and demonstrate that coupling-induced spectral shifts are significantly stronger for surface modes than for edge modes. The experimental data correspond well to numerical simulations. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6302311PMC
December 2018
3 Reads

Finite-Size Effects in Metasurface Lasers Based on Resonant Dark States.

ACS Photonics 2018 Sep 24;5(9):3788-3793. Epub 2018 Aug 24.

Institute of Electronic Structure and Laser, FORTH, 71110 Heraklion, Crete, Greece.

The quest for subwavelength coherent light sources has recently led to the exploration of dark-mode based surface lasers, which allow for independent adjustment of the lasing state and its coherent radiation output. To understand how this unique design performs in real experiments, we need to consider systems of finite size and quantify finite-size effects not present in the infinite dark-mode surface laser model. Here we find that, depending on the size of the system, distinct and even counterintuitive behavior of the lasing state is possible, determined by a balanced competition between multiple loss channels, including dissipation, intentional out-coupling of coherent radiation, and leakage from the edges of the finite system. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00835DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6219820PMC
September 2018
2 Reads

One-Directional Antenna Systems: Energy Transfer from Monomers to J-Aggregates within 1D Nanoporous Aluminophosphates.

ACS Photonics 2018 Jan 19;5(1):151-157. Epub 2017 Oct 19.

Departamento de Química Física, Universidad del País Vasco, UPV/EHU, Apartado 644, 48080 Bilbao, Spain.

A cyanine dye (PIC) was occluded into two 1D-nanopoporus Mg-containing aluminophosphates with different pore size (MgAPO-5 and MgAPO-36 with AFI and ATS zeolitic structure types, with cylindrical channels of 7.3 Å diameter and elliptical channels of 6.7 Å × 7. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b00553DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6197758PMC
January 2018
3 Reads

Adaptive Control of Necklace States in a Photonic Crystal Waveguide.

ACS Photonics 2018 Oct 14;5(10):3984-3988. Epub 2018 Sep 14.

Complex Photonic Systems (COPS), MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

Resonant cavities with high quality factor and small mode volume provide crucial enhancement of light-matter interactions in nanophotonic devices that transport and process classical and quantum information. The production of functional circuits containing many such cavities remains a major challenge, as inevitable imperfections in the fabrication detune the cavities, which strongly affects functionality such as transmission. In photonic crystal waveguides, intrinsic disorder gives rise to high- localized resonances through Anderson localization; however their location and resonance frequencies are completely random, which hampers functionality. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.8b01038
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http://dx.doi.org/10.1021/acsphotonics.8b01038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195811PMC
October 2018
31 Reads

Power Balance and Temperature in Optically Pumped Spasers and Nanolasers.

ACS Photonics 2018 Sep 24;5(9):3695-3703. Epub 2018 Aug 24.

Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040, Linz, Austria.

Spasers and nanolasers produce a significant amount of heat, which impedes their realizability. We numerically investigate the farfield emission and thermal load in optically pumped spasers with a coupled electromagnetic/thermal model, including additional temperature discontinuities due to interfacial Kapitza resistance. This approach allows to explore multiple combinations of constitutive materials suitable for robust manufacturable spasers. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.8b00705
Publisher Site
http://dx.doi.org/10.1021/acsphotonics.8b00705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6156092PMC
September 2018
19 Reads

DNA Origami Route for Nanophotonics.

ACS Photonics 2018 Apr 12;5(4):1151-1163. Epub 2018 Feb 12.

Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany.

The specificity and simplicity of the Watson-Crick base pair interactions make DNA one of the most versatile construction materials for creating nanoscale structures and devices. Among several DNA-based approaches, the DNA origami technique excels in programmable self-assembly of complex, arbitrary shaped structures with dimensions of hundreds of nanometers. Importantly, DNA origami can be used as templates for assembly of functional nanoscale components into three-dimensional structures with high precision and controlled stoichiometry. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01580DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6156112PMC
April 2018
7 Reads

Nonlinear Photoacoustic Imaging by Multiphoton Upconversion and Energy Transfer.

ACS Photonics 2017 Nov 11;4(11):2699-2705. Epub 2017 Oct 11.

Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, New York 14260, USA.

In recent years, photoacoustic tomography (PAT) is increasingly used in biomedical research, as it allows for direct visualization of optical absorption in deep tissue. In addition to vascular and hemodynamic imaging using endogenous contrasts, PAT is also capable of imaging neural and molecular dynamics with extrinsic contrasts. While near-infrared (NIR)-absorbing contrasts are preferred for deep tissue imaging, compared to visible-light-absorbing contrasts, they are much harder to design and synthesize with good environmental stability. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b00399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150608PMC
November 2017
7 Reads

Exciton Fine Structure and Lattice Dynamics in InP/ZnSe Core/Shell Quantum Dots.

ACS Photonics 2018 Aug 17;5(8):3353-3362. Epub 2018 Jul 17.

Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands.

Nanocrystalline InP quantum dots (QDs) hold promise for heavy-metal-free optoelectronic applications due to their bright and size-tunable emission in the visible range. Photochemical stability and high photoluminescence (PL) quantum yield are obtained by a diversity of epitaxial shells around the InP core. To understand and optimize the emission line shapes, the exciton fine structure of InP core/shell QD systems needs be investigated. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00615DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115013PMC
August 2018
10 Reads

Plasmon-Enhanced Single-Molecule Enzymology.

ACS Photonics 2018 Aug 23;5(8):3073-3081. Epub 2018 May 23.

Molecular Biosensing for Medical Diagnostics, Faculty of Applied Physics, and Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, The Netherlands.

We present a numerical study on plasmon-enhanced single-molecule enzymology. We combine Brownian dynamics and electromagnetic simulations to calculate the enhancement of fluorescence signals of fluorogenic substrate converted by an enzyme conjugated to a plasmonic particle. We simulate the Brownian motion of a fluorescent product away from the active site of the enzyme, and calculate the photon detection rate taking into account modifications of the excitation and emission processes by coupling to the plasmon. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6105035PMC
August 2018
20 Reads

Plasmonic Enhancement of Two-Photon-Excited Luminescence of Single Quantum Dots by Individual Gold Nanorods.

ACS Photonics 2018 Jul 11;5(7):2960-2968. Epub 2018 Jun 11.

Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, The Netherlands.

Plasmonic enhancement of two-photon-excited fluorescence is not only of fundamental interest but also appealing for many bioimaging and photonic applications. The high peak intensity required for two-photon excitation may cause shape changes in plasmonic nanostructures, as well as transient plasmon broadening. Yet, in this work, we report on strong enhancement of the two-photon-excited photoluminescence of single colloidal quantum dots close to isolated chemically synthesized gold nanorods. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057742PMC
July 2018
4 Reads

Rapid Voltage Sensing with Single Nanorods via the Quantum Confined Stark Effect.

ACS Photonics 2018 Jul 24;5(7):2860-2867. Epub 2018 Jun 24.

Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.

Properly designed colloidal semiconductor quantum dots (QDs) have already been shown to exhibit high sensitivity to external electric fields via the quantum confined Stark effect (QCSE). Yet, detection of the characteristic spectral shifts associated with the effect of the QCSE has traditionally been painstakingly slow, dramatically limiting the sensitivity of these QD sensors to fast transients. We experimentally demonstrate a new detection scheme designed to achieve shot-noise-limited sensitivity to emission wavelength shifts in QDs, showing feasibility for their use as local electric field sensors on the millisecond time scale. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.8b00206
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http://dx.doi.org/10.1021/acsphotonics.8b00206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6053642PMC
July 2018
5 Reads

High Internal Emission Efficiency of Silicon Nanoparticles Emitting in the Visible Range.

ACS Photonics 2018 Jun 10;5(6):2129-2136. Epub 2018 Apr 10.

Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.

Light-emitting silicon nanoparticles (Si-NPs) are interesting for lighting applications due to their nontoxicity, chemical robustness, and photostability; however, they are not practically considered due to their low emission efficiencies. While large Si-NPs emitting in the red to infrared spectral region show ensemble emission quantum efficiencies up to 60%, the emission efficiencies of smaller Si-NPs, emitting in the visible spectral range, are far lower, typically below 10-20%. In this work, we test this efficiency limit by measuring for the first time the internal quantum efficiency (IQE), i. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019024PMC
June 2018
7 Reads

Trion-Polariton Formation in Single-Walled Carbon Nanotube Microcavities.

ACS Photonics 2018 Jun 8;5(6):2074-2080. Epub 2018 May 8.

Institute for Physical Chemistry, Universität Heidelberg, D-69120 Heidelberg, Germany.

We demonstrate the formation and tuning of charged trion-polaritons in polymer-sorted (6,5) single-walled carbon nanotubes in a planar metal-clad microcavity at room temperature. The positively charged trion-polaritons were induced by electrochemical doping and characterized by angle-resolved reflectance and photoluminescence spectroscopy. The doping level of the nanotubes within the microcavity was controlled by the applied bias and thus enabled tuning from mainly excitonic to a mixture of exciton and trion transitions. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019025PMC
June 2018
2 Reads

Planar Double-Epsilon-Near-Zero Cavities for Spontaneous Emission and Purcell Effect Enhancement.

ACS Photonics 2018 Jun 23;5(6):2287-2294. Epub 2018 Mar 23.

Nanochemistry Department, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.

The enhancement of the photophysical response of fluorophores is a crucial factor for photonic and optoelectronic technologies that involve fluorophores as gain media. Recent advances in the development of an extreme light propagation regime, called epsilon-near-zero (ENZ), provide a promising approach in this respect. In this work, we design metal/dielectric nanocavities to be resonant with the absorption and emission bands of the employed fluorophores. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6906952PMC

Analyses of Intravesicular Exosomal Proteins Using a Nano-Plasmonic System.

ACS Photonics 2018 Feb 3;5(2):487-494. Epub 2017 Nov 3.

Center for Systems Biology, Massachusetts General Hospital, 185 Cambridge St, CPZN 5206, Boston, MA 02114.

Extracellular vesicles (EVs), including exosomes, are nanoscale membrane particles shed from cells and contain cellular proteins whose makeup could inform cancer diagnosis and treatment. Most analyses have focused on surface proteins while analysis of intravesicular proteins has been more challenging. Herein, we report an EV screening assay for both intravesicular and transmembrane proteins using a nanoplasmonic sensor. Read More

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http://pubs.acs.org/doi/10.1021/acsphotonics.7b00992
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http://dx.doi.org/10.1021/acsphotonics.7b00992DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966285PMC
February 2018
4 Reads

Terahertz Magnon-Polaritons in TmFeO.

ACS Photonics 2018 Apr 1;5(4):1375-1380. Epub 2018 Feb 1.

Radboud University, Institute for Molecules and Materials, Nijmegen, The Netherlands.

Magnon-polaritons are shown to play a dominant role in the propagation of terahertz (THz) waves through TmFeO orthoferrite, if the frequencies of the waves are in the vicinity of the quasi-antiferromagnetic spin resonance mode. Both time-domain THz transmission and emission spectroscopies reveal clear beatings between two modes with frequencies slightly above and slightly below this resonance, respectively. Rigorous modeling of the interaction between the spins of TmFeO and the THz light shows that the frequencies correspond to the upper and lower magnon-polariton branches. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5953567PMC
April 2018
23 Reads

How Dark Are Radial Breathing Modes in Plasmonic Nanodisks?

ACS Photonics 2018 Mar 12;5(3):861-866. Epub 2017 Dec 12.

Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud, 91405 Orsay, France.

Due to a vanishing dipole moment, radial breathing modes in small flat plasmonic nanoparticles do not couple to light and have to be probed with a near-field source, as in electron energy loss spectroscopy (EELS). With increasing particle size, retardation gives rise to light coupling, enabling probing breathing modes optically or by cathodoluminescence (CL). Here, we investigate single silver nanodisks with diameters of 150-500 nm by EELS and CL in an electron microscope and quantify the EELS/CL ratio, which corresponds to the ratio of full to radiative damping of the breathing mode. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871341PMC
March 2018
5 Reads

Antimatched Electromagnetic Metasurfaces for Broadband Arbitrary Phase Manipulation in Reflection.

ACS Photonics 2018 Mar 3;5(3):1101-1107. Epub 2018 Jan 3.

Institute of Electronic Structure and Laser, FORTH, GR-71110 Heraklion, Crete, Greece.

Metasurfaces impart phase discontinuities on impinging electromagnetic waves that are typically limited to 0-2π. Here, we demonstrate that multiresonant metasurfaces can break free from this limitation and supply arbitrarily large, tunable time delays over ultrawide bandwidths. As such, ultrathin metasurfaces can act as the equivalent of thick bulk structures by emulating the multiple geometric resonances of three-dimensional systems that originate from phase accumulation with effective material resonances implemented on the surface itself via suitable subwavelength meta-atoms. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5865077PMC
March 2018
4 Reads

Ab Initio Optimized Effective Potentials for Real Molecules in Optical Cavities: Photon Contributions to the Molecular Ground State.

ACS Photonics 2018 Mar 9;5(3):992-1005. Epub 2018 Jan 9.

Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany.

We introduce a simple scheme to efficiently compute photon exchange-correlation contributions due to the coupling to transversal photons as formulated in the newly developed quantum-electrodynamical density-functional theory (QEDFT).1-5 Our construction employs the optimized-effective potential (OEP) approach by means of the Sternheimer equation to avoid the explicit calculation of unoccupied states. We demonstrate the efficiency of the scheme by applying it to an exactly solvable GaAs quantum ring model system, a single azulene molecule, and chains of sodium dimers, all located in optical cavities and described in full real space. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b01279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5865078PMC
March 2018
3 Reads

Near-Infrared and Optical Beam Steering and Frequency Splitting in Air-Holes-in-Silicon Inverse Photonic Crystals.

ACS Photonics 2017 Nov 28;4(11):2782-2788. Epub 2017 Sep 28.

Institute of Electronic Structure and Laser, FORTH, 71110, Heraklion, Crete, Greece.

We present the design of a dielectric inverse photonic crystal structure that couples line-defect waveguide propagating modes into highly directional beams of controllable directionality. The structure utilizes a triangular lattice made of air holes drilled in an infinitely thick Si slab, and it is designed for operation in the near-infrared and optical regime. The structure operation is based on the excitation and manipulation of dark dielectric surface states, in particular on the tailoring of the dark states' coupling to outgoing radiation. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b00739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840860PMC
November 2017
4 Reads

Hot Carrier Generation and Extraction of Plasmonic Alloy Nanoparticles.

ACS Photonics 2017 May 6;4(5):1146-1152. Epub 2017 Mar 6.

Materials for Energy Conversion and Storage (MECS), Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft 2628-BL, The Netherlands.

The conversion of light to electrical and chemical energy has the potential to provide meaningful advances to many aspects of daily life, including the production of energy, water purification, and optical sensing. Recently, plasmonic nanoparticles (PNPs) have been increasingly used in artificial photosynthesis (e.g. Read More

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http://dx.doi.org/10.1021/acsphotonics.6b01048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5770161PMC
May 2017
4 Reads

Single-Photon Nanoantennas.

ACS Photonics 2017 Apr 10;4(4):710-722. Epub 2017 Mar 10.

Center for Nanophotonics, AMOLF, Science Park 104, NL-1098XG, Amsterdam, The Netherlands.

Single-photon nanoantennas are broadband strongly scattering nanostructures placed in the near field of a single quantum emitter, with the goal to enhance the coupling between the emitter and far-field radiation channels. Recently, great strides have been made in the use of nanoantennas to realize fluorescence brightness enhancements, and Purcell enhancements, of several orders of magnitude. This perspective reviews the key figures of merit by which single-photon nanoantenna performance is quantified and the recent advances in measuring these metrics unambiguously. Read More

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http://dx.doi.org/10.1021/acsphotonics.7b00061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5770162PMC
April 2017
9 Reads

Robust Extraction of Hyperbolic Metamaterial Permittivity using Total Internal Reflection Ellipsometry.

ACS Photonics 2018 ;5

Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.

Hyperbolic metamaterials are optical materials characterized by highly anisotropic effective permittivity tensor components having opposite signs along orthogonal directions. The techniques currently employed for characterizing the optical properties of hyperbolic metamaterials are limited in their capability for robust extraction of the complex permittivity tensor. Here we demonstrate how an ellipsometry technique based on total internal reflection can be leveraged to extract the permittivity of hyperbolic metamaterials with improved robustness and accuracy. Read More

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http://dx.doi.org/10.1021/acsphotonics.8b00086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463533PMC
January 2018
1 Read