The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Using scanning Kerr-rotation microscopy, we directly image the injection and subsequent transport of spin-polarized electrons in semiconductors. We discuss optical spin injection as well as electrical spin injection in hybrid Fe/GaAs spin transport devices.
Using near-degenerate optical parametric oscillator operating at ~2 microns as a dual-wavelength pump source, we generated tunable THz radiation near 2 THz, at a microwatt power level, with TM0 propagation mode of a planar GaAs waveguide.
Simultaneous near-field fluorescence lifetime imaging and atomic force microscopy identify radiative, interface and subsurface defect recombination sites in GaAs/GaInP heterostructures. Such unique characterization plays a significant role in identifying candidate samples for laser cooling.
By incorporating GaAs/AlGaAs based uni-traveling-carrier photodiodes with broadband micromachined monopole antennas, the demonstrated photonic-transmitter can radiate strong sub-THz pulses (20mW peak-power) with a wide bandwidth (100~250GHz), which was measured by another photonic-receiver for ultra-wideband communication.
We report our investigation of catastrophic optical damaged high power multi-mode InGaAs-AlGaAs strained quantum well (QW) lasers using electron beam induced current (EBIC), focused ion beam (FIB), and high-resolution transmission electron microscope (HR-TEM) techniques.
Plasma resonance of electrons was observed in an antenna-coupled GaAs metal-semiconductor-field-effect-transistor (MESFET) by sweeping bias voltages. This resonant absorption was used to realize a room temperature terahertz detector.
High Q-factor (~60,000) whispering gallery modes are observed from GaAs based micropillar cavities with embedded InAs quantum dots. Low threshold lasing is observed in WGMs near to the peak of the QD ensemble.
Near-field optical spectroscopy of nanoscale Ga droplets on GaAs exhibits quenching of photoluminescence emission due to coupling with surface plasmon. Ga droplets exhibit antenna like behavior associated with a red-shift in the near-field photoluminescence emission.
We report the first room temperature CW operation of two dimensional single-mode edge-emitting photonic crystal Bragg lasers. Single-mode lasing with single-lobed, diffraction limited far-fields is obtained for 100mum wide and 550 mum long on-chip devices.
Time-resolved electro-absorption is reported for the first time in a GaInNAs quantum well p-i-n waveguide at 1.3 mum. A recovery of 55 ps demonstrates the potential for optical modulator devices.
Substrate- removed GaAs/AlGaAs nanowire phase modulators with 0.51 V pi phase shift efficiency were fabricated. Quasi push-pull driven Mach-Zehnder intensity modulators made out of these phase modulators have record low 0.3 V drive voltage for 7 mm long electrode.
An efficient OP-GaAs OPO pumped by a high repetition rate (20-50 kHz) Q-switched Ho:YAG laser is presented. The slope efficiency is 53% at 20 kHz. Influence of pump polarization on OPO performance is tested.
GaAs nano-wire waveguides were successfully fabricated on a SiO2/Si substrate for the first time. 15 dB cross loss modulation was achieved by a few mW continuous-wave pump power within a 1.5 mm-long waveguide.
Narrowband THz radiation drives transitions between bound electron states in GaAs neutral donors. Elastic light scattering from a donor bound exciton resonance allows time-resolved measurements of the excited state lifetime and THz-induced AC Stark effect.
We describe the operation of a femtosecond Cr4+:YAG laser that has been mode locked using a novel GaInNAsSb SESAM. 230 fs pulses were generated at an average output power of 280 mW.
Time-resolved mid-infrared upconversion based on sum-frequency generation was applied to measure the group-velocity dispersion in quantum cascade lasers; material, waveguide, and gain contributions were distinguished, and used to model the temporal pulse broadening.
We have theoretically estimated optical isolation of larger than 30 dB in Co-InGaAsP semiconductor active optical isolators based on nonreciprocal phase shift. The length of the nonreciprocal phase shifting region is as short as 1.3 mm.
We report novel single-crystalline (In)GaAs nanoneedles with 2~5 nm tips, smooth 6-9deg taper angles and lengths up to 3-4 mum, grown aligned to [111] orientation on Si substrates. Bright photoluminescence is obtained from quantum-well nanoneedles.
The growth of self-aligned planar GaAs nanowires on GaAs (100) substrates is demonstrated using Au-catalyzed metalorganic chemical vapor deposition (MOCVD). The effect of growth temperature on nanowire orientation and the growth mechanism are discussed.
We report on the coherent coupling between surface plasmon polaritons and quantum well excitons in a hybrid metal-semiconductor nanostructure. The coupling is probed by angle-resolved low temperature spectroscopy and analyzed within a coupled oscillator model.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.