A5035750419- Semiconductor Quantum Structures and Devices
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Strong Light-Matter Interactions
- Molecular Junctions and Nanostructures
- Terahertz technology and applications
- Quantum and electron transport phenomena
- Photonic and Optical Devices
- Quantum Information and Cryptography
- Mechanical and Optical Resonators
- Advanced Optical Sensing Technologies
- Advanced Condensed Matter Physics
- Advanced Antenna and Metasurface Technologies
- Acoustic Wave Resonator Technologies
- Semiconductor Lasers and Optical Devices
- Metamaterials and Metasurfaces Applications
- Semiconductor materials and devices
- Orbital Angular Momentum in Optics
- Ga2O3 and related materials
- GaN-based semiconductor devices and materials
- Advanced Photocatalysis Techniques
- Photocathodes and Microchannel Plates
- Multiferroics and related materials
- Advancements in Semiconductor Devices and Circuit Design
Yulin Normal University
2023
Huanghuai University
2022
National Institute of Standards and Technology
2002-2008
University of South Carolina
2003
University of California, Santa Barbara
1997-2003
We have probed the internal structure and nonlinear response of magnetoexcitons in GaAs/AlGaAs quantum wells by resonantly driving one- two-photon transitions with intense terahertz electric fields. Strong near-band-gap emission lines, or optical sidebands, appear at frequencies ${\ensuremath{\omega}}_{\mathrm{NIR}}\ifmmode\pm\else\textpm\fi{}2n{\ensuremath{\omega}}_{\mathrm{THz}}$, where ${\ensuremath{\omega}}_{\mathrm{NIR}}$ is interband exciton-creation frequency,...
Abstract When the in-plane inversion symmetry is broken, it leads to intercoupling between free space and eigenmodes, thereby establishing a radiation channel for bound states in continuum (BIC). Consequently, BIC evolve into quasi-bound (q-BIC), which are protected by symmetry. The q-BIC then forms Pancharatnam-Berry (PB) phase upon induction of its topological Gaussian circularly polarized wave. This process results an optical vortex (OV) with charge l=+2. Creation this OV does not require...
We investigate the operation of a quantum dot, optically gated, field-effect transistor as photon detector. The detector exhibits time-gated, single-shot, single-photon sensitivity, linear response, and an internal efficiency up to (68±18)% at 4K. Given noise system, they find that particular discriminator level can be chosen so device operates with (53±11)% dark counts 0.003 per shot.
We have generated first-order tetrahertz (THz) optical sidebands on a near-infrared (NIR) probe beam by driving an excitonic intersubband resonance with THz electric fields. use radiation polarized along the noncentrosymmetric axis of quantum well system to generate comb ωsideband=ωNIR+nωTHz. The n=1 process offers efficient means modulating NIR carrier at frequencies and yields new spectroscopic information transitions.
We investigated the growth of GaN/Al0.20Ga0.80N multiple quantum wells (MQWs) on selective-area-grown a-plane GaN pillars over r-plane sapphire. In contrast to MQWs grown planar templates, these GaN/Al0.20Ga0.8N exhibited pit-free and atomically smooth surface morphology. Their structural quality their UV emission (at 357 nm) increased with underlying pillar height. The epitaxy GaN/AlGaN is thus a promising simple approach for fabricating stripe-geometry, high-efficiency, nonpolar emitters.
An undoped double quantum well (DQW) was driven with a terahertz (THz) electric field of frequency ωTHz polarized in the growth direction, while simultaneously illuminated near-infrared (NIR) laser at ωNIR. The intensity NIR upconverted sidebands ωsideband=ωNIR+ωTHz maximized when dc voltage applied direction tuned excitonic states into resonance both THz and fields. There no detectable upconversion far from resonance. results demonstrate possibility using gated DQW devices for all-optical...
Driving a double-quantum-well excitonic intersubband resonance with terahertz (THz) electric field of frequency ${\ensuremath{\omega}}_{\mathrm{THz}}$ generated optical sidebands $\ensuremath{\omega}={\ensuremath{\omega}}_{\mathrm{THz}}+{\ensuremath{\omega}}_{\mathrm{NIR}}$ on weak near-infrared probe. At high THz intensities, the dipole energy which coupled two excitons was comparable to photon energy. In this strong-field regime, sideband intensity displayed nonmonotonic dependence...
We describe the design of epitaxial layers for an efficient, photon-number-determining detector that utilizes a layer self-assembled quantum dots as optically addressable gate in field-effect transistor. Our features dedicated absorption where photoexcited holes are produced and directed with tailored electric fields to dot layer. A barrier ensures is located at two-dimensional potential minimum structure efficient collection holes. Using charge traps allows us contain well-defined plane....
We have investigated the linear and nonlinear response of confined magnetoexcitons to intense terahertz (THz) radiation. By monitoring photoluminescence from THz-driven GaAs quantum wells, we observed for first time internal transitions in direct excitons. The spectrum excitations is enriched by complexities valence band well explained an effective-mass theory. At high THz-field strengths, emission properties driven wells are completely dominated new near-band-gap features, or optical...
By monitoring changes in excitonic photoluminescence (PL) that are induced by terahertz (THz) radiation, we observe resonant THz absorption magnetoexcitons ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ quantum wells. Changes the PL spectrum explored as a function of temperature and magnetic field, providing insight into mechanisms which allow to modulate PL. The strongest PL-quenching occurs at heavy hole...
The double InGaAs/InAs channel structure is designed to improve DC and RF characteristics of InP-based HEMT, which studied by the numerical simulation. saturated current, transconductance, subthreshold slope, drain induced barrier lowering, frequency are analyzed. A comparison done between device with InGaAs channel. By using channel, maximum transconductance 1019.7 mS/mm achieved, lower value slope lowering also obtained. excellent performance mainly due enhanced confinement electrons in...
Summary form only given. We performed experiments where a near-infrared (NIR) probe laser beam is mixed with an intense terahertz (THz) pump in gated, asymmetric double quantum-well The THz field couples to excitonic intersubband excitation while the NIR interband excitation.
We have probed the internal structure and nonlinear response of magnetoexcitons in GaAs/AlGaAs quantum wells by resonantly driving one- two-photon transitions with intense terahertz electric fields. Strong near-bandgap emission lines, or optical sidebands, appear at frequencies ωNIR ± 2nωTHz, where is interband exciton-creation frequency, ωTHz frequency field, n an integer. The intensity sidebands exhibits pronounced enhancement when coincides between magnetically tuned energy levels...
Here we report enhanced spontaneous emission intensity in AlOx/GaAs micropillars with InGaAs quantum dot (QD) ensemble emitters, measured using photoluminescence (PL). The PL from the QD was emitted into discrete transverse micropillar modes. We then spectrum of pillars whose outer rim is replaced an increasing number concentric rings to form a high-order circular grating. As more periods were added grating, narrow mode suppressed and became dominated by broad grating-extracted mode.
We have probed the linear and nonlinear terahertz (THz) properties of magnetoexcitons in GaAs/AlGaAs quantum wells. By monitoring photoluminescence from wells that were simultaneously driven by THz fields, we directly observed internal transitions excitons. In nonlinear, high-THz-excitation regime, mixing optical radiation, which resulted sidebands. sidebands, one- two-THz-photon These results provide new accurate information on energy structure dynamics