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Tailoring dielectric resonator geometries for directional scattering, Huygens' metasurfaces, and high quality-factor Fano resonances

2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.; Luk, Ting S.; Wendt, J.R.; Liu, Sheng L.; Brener, Igal B.; Sinclair, Michael B.

Metamaterial dielectric resonators represent a promising path toward low-loss metamaterials at optical frequencies. In this paper we utilize perturbations of high symmetry resonator geometries, such as cubes, either to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering and Huygens' metasurfaces, or to induce couplings between the otherwise orthogonal resonator modes to achieve high-quality factor Fano resonances. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.

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Resonantly Enhanced Second-Harmonic Generation Using III-V Semiconductor All-Dielectric Metasurfaces

Nano Letters

Liu, Sheng L.; Sinclair, Michael B.; Saravi, Sina; Keeler, Gordon A.; Yang, Yuanmu Y.; Reno, J.L.; Peake, Gregory M.; Setzpfandt, Frank; Staude, Isabelle; Pertsch, Thomas; Brener, Igal B.

Nonlinear optical phenomena in nanostructured materials have been challenging our perceptions of nonlinear optical processes that have been explored since the invention of lasers. For example, the ability to control optical field confinement, enhancement, and scattering almost independently allows nonlinear frequency conversion efficiencies to be enhanced by many orders of magnitude compared to bulk materials. Also, the subwavelength length scale renders phase matching issues irrelevant. Compared with plasmonic nanostructures, dielectric resonator metamaterials show great promise for enhanced nonlinear optical processes due to their larger mode volumes. Here, we present, for the first time, resonantly enhanced second-harmonic generation (SHG) using gallium arsenide (GaAs) based dielectric metasurfaces. Using arrays of cylindrical resonators we observe SHG enhancement factors as large as 104 relative to unpatterned GaAs. At the magnetic dipole resonance, we measure an absolute nonlinear conversion efficiency of ∼2 × 10-5 with ∼3.4 GW/cm2 pump intensity. The polarization properties of the SHG reveal that both bulk and surface nonlinearities play important roles in the observed nonlinear process.

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Epsilon-near-zero modes for tailored light-matter interaction

Physical Review Applied

Campione, Salvatore; Liu, Sheng L.; Benz, Alexander; Klem, John F.; Sinclair, Michael B.; Brener, Igal B.

Epsilon-near-zero (ENZ) modes arising from condensed-matter excitations such as phonons and plasmons are a new path for tailoring light-matter interactions at the nanoscale. Complex spectral shaping can be achieved by creating such modes in nanoscale semiconductor layers and controlling their interaction with multiple, distinct, dipole resonant systems. Examples of this behavior are presented at midinfrared frequencies for ENZ modes that are strongly coupled to metamaterial resonators and simultaneously strongly coupled to semiconductor phonons or quantum-well intersubband transitions (ISTs), resulting in double- and triple-polariton branches in transmission spectra. For the double-polariton branch case, we find that the best strategy to maximize the Rabi splitting is to use a combination of a doped layer supporting an ENZ feature and a layer supporting ISTs, with overlapping ENZ and IST frequencies. This design flexibility renders this platform attractive for low-voltage tunable filters, light-emitting diodes, and efficient nonlinear composite materials.

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Tunable Quantum Dot Solids: Impact of Interparticle Interactions on Bulk Properties

Sinclair, Michael B.; Fan, Hongyou F.; Brener, Igal B.; Luk, Ting S.; Liu, Sheng L.

QD-solids comprising self-assembled semiconductor nanocrystals such as CdSe are currently under investigation for use in a wide array of applications including light emitting diodes, solar cells, field effect transistors, photodetectors, and biosensors. The goal of this LDRD project was develop a fundamental understanding of the relationship between nanoparticle interactions and the different regimes of charge and energy transport in semiconductor quantum dot (QD) solids. Interparticle spacing was tuned through the application of hydrostatic pressure in a diamond anvil cell, and the impact on interparticle interactions was probed using x-ray scattering and a variety of static and transient optical spectroscopies. During the course of this LDRD, we discovered a new, previously unknown, route to synthesize semiconductor quantum wires using high pressure sintering of self-assembled quantum dot crystals. We believe that this new, pressure driven synthesis approach holds great potential as a new tool for nanomaterials synthesis and engineering.

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Phased-array sources based on nonlinear metamaterial nanocavities

Nature Communications

Wolf, Omri W.; Campione, Salvatore; Benz, Alexander; Ravikumar, Arvind P.; Liu, Sheng L.; Luk, Ting S.; Kadlec, Emil A.; Shaner, Eric A.; Klem, John F.; Sinclair, Michael B.; Brener, Igal B.

Coherent superposition of light from subwavelength sources is an attractive prospect for the manipulation of the direction, shape and polarization of optical beams. This phenomenon constitutes the basis of phased arrays, commonly used at microwave and radio frequencies. Here we propose a new concept for phased-array sources at infrared frequencies based on metamaterial nanocavities coupled to a highly nonlinear semiconductor heterostructure. Optical pumping of the nanocavity induces a localized, phase-locked, nonlinear resonant polarization that acts as a source feed for a higher-order resonance of the nanocavity. Varying the nanocavity design enables the production of beams with arbitrary shape and polarization. As an example, we demonstrate two second harmonic phased-array sources that perform two optical functions at the second harmonic wavelength (∼5μm): a beam splitter and a polarizing beam splitter. Proper design of the nanocavity and nonlinear heterostructure will enable such phased arrays to span most of the infrared spectrum.

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Tailored light-matter interaction through epsilon-near- zero modes

CLEO: QELS - Fundamental Science, CLEO_QELS 2015

Campione, Salvatore; Liu, Sheng L.; Benz, Alexander; Klem, John F.; Sinclair, Michael B.; Brener, Igal B.

We use epsilon-near-zero modes in semiconductor nanolayers to design a system whose spectral properties are controlled by their interaction with multi-dipole resonances. This design flexibility renders our platform attractive for efficient nonlinear composite materials. © OSA 2015.

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Third harmonic generation in ultrathin epsilon-near-zero media

CLEO: Science and Innovations, CLEO-SI 2015

Luk, Ting S.; De Ceglia, Domenico; Keeler, Gordon A.; Prasankumar, Rohit P.; Vincenti, Maria A.; Liu, Sheng L.; Scalora, Michael; Sinclair, Michael B.; Campione, Salvatore

We demonstrate efficient third harmonic generation from a 21.6nm-thick indium tin oxide film on glass substrate for a pump fundamental wavelength of 1350nm using the field enhancement properties of optical modes supported by epsilon-near-zero media. © OSA 2015.

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Results 101–125 of 328
Results 101–125 of 328