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An optical delay variable between 0 to 161 ps with GHz bandwidth is demonstrated in an InGaAsP quantum-well semiconductor optical amplifier and modeled by population oscillation and nearly degenerate four-wave-mixing effects for the first time.
Spin gratings lasting longer than the carrier lifetime are measured in lightly n-doped quantum wells. In a magnetic field, precession of the grating is observed, and diffusion rates are determined by varying the grating period.
The 1.55 mum pulsed operation of an optically-pumped GaInNAsSb vertical-cavity surface emitting laser (VCSEL) is reported. Full temperature (10-50degC) and wavelength-dependent (1540-1560 nm) laser measurements were recorded. The annealing effect on laser performance is also shown.
We demonstrate a muW-level broadly tunable THz source based on parametric down-conversion in orientation-patterned GaAs pumped by femtosecond pulses from a Tm-doped fiber laser. Generated THz powers should be scalable to mW-levels with this approach.
We demonstrate efficient generation of narrow-bandwidth THz waveforms in optically-contacted multi-layer and orientation-patterned GaAs, using optical rectification of 2-4 mum, 100-fs pump pulses. THz waveforms were directly measured using two-color time-domain spectroscopy.
We demonstrate characteristics of InAs/GaAs quantum-dot photonic-crystal lasers with high spontaneous emission coupling efficiencies and soft-turn-on behaviors. Pronounced bunching signals subside with the increase of pumping, revealing the onset of lasing operations.
We report high-performance single-frequency operation of a directly diode pumped GaSb vertical-external-cavity surface-emitting laser (VECSEL) at 2.3 mum. Tunability of >25 nm with a maximum single frequency output of 0.68 W is demonstrated.
We report lasing of optically pumped Ga(AsNP)/GaP multiple quantum-well structures grown pseudomorphically on GaP substrate. A distinct threshold behaviour is observed at both cryogenic and room temperature; modal gain of up to 20 cm-1 is determined.
The spectral width of terahertz emission from ion-implanted terahertz emitters increases with ion damage, owing to ultrafast carrier capture. Carrier dynamics simulations reinforce these findings. Optical-pump, terahertz-probe experiments confirm the sub-picosecond lifetimes of these materials.
We report the first realization of a monolithic vertical-cavity, surface emitting micro optical parametric conversion nanostructure, triply resonant with the parametric frequencies, allowing parametric oscillation or amplification with a very low pump power threshold.
Lasing behavior under optical pumping conditions is reported for photonic crystal double-heterostructure nanocavities with InAs quantum dot active regions. Coupling of this laser emission into a photonic crystal waveguide is also reported.
An ultrabroad infrared continuum can be produced using optical parametric generation (OPG) in quasi-phasematched GaAs. Spectra over an octave wide, spanning 4.5 to 10.7 microns, measured 20 dB down from the peak, have been observed.
We present a comprehensive many-particle theory for optical refrigeration of bulk GaAs via luminescence up-conversion. We predict cooling in the regime of a partially ionized exciton gas and discuss its temperature dependence.
We report the first observation of near-infrared (NIR) lasing in subwavelength semiconductor wires. The optically-pumped GaSb subwavelength-wire-based lasers promise to be useful for future NIR photonic integrated circuits and systems.
Electrically pulsed GaInNAsSb-based, vertical cavity surface emitting lasers (VCSELs) at 1534 nm are reported. The lasers operated below -25C due to a gain-cavity misalignment. These are the first monolithic, C-band VCSELs on GaAs.
Terahertz (THz) radiation from p-type (100) InAs was investigated using time domain spectroscopy. Azimuthal angle dependence measurements and the ambipolar mobility theory suggest the dominant THz radiation mechanism to be that of the surge current.
Room temperature carrier lifetimes of both type-I and type-II InP-based multiple quantum wells near optical transparency were measured using the pump-probe technique. Longer carrier lifetime in the type-II sample was observed.
A Si laser with a Si micro-disk evanescently coupled to a III-V gain medium is proposed. The III-V also functions as a DBR at the gain wavelength to minimize the perturbation of the cavity mode.
Experimental studies of nearly degenerate time-resolved Faraday rotation (TRFR) in GaAs and InGaAs quantum wells show that many body interactions between excitons strongly modify the TRFR response from the electron spin coherence.
Femtosecond two-color pump-probe experiments on intersubband absorption spectra of electrons in a GaN/AlN superlattice show distinct spectral holes unraveling both the homogeneous broadening contribution and the underlying optical phonon progression.
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