We present experimental observations of a nonresonant dynamic Stark shift in strongly coupled microcavity quantum well exciton polaritons--a system which provides a rich variety of solid-state collective phenomena. The Stark effect is demonstrated in a GaAs/AlGaAs system at 10 K by femtosecond pump-probe measurements, with the blueshift approaching the meV scale for a pump fluence of 2  mJ cm(-...

We demonstrate broadband infrared pulse shaping by difference-frequency mixing of two visible phase-locked linearly chirped pulses in GaAs. Control of the temporal profile of the emitted field is achieved through this direct tailoring of the exciting visible intensity. The results are in agreement with a simulation with no adjustable parameter.

A comprehensive study of the electroluminescence of four longwavelength microcavity devices with InAs/GaInAs quantum dot active regions emitting near 1.3 μm was conducted. The four molecular beam epitaxial grown samples with AlAs oxide aperture confinement layers were fabricated, characterized, and optically modeled. Optical power transmission of the samples was modeled using Matlab and compare...

We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement of the spin dephasing time, T2*, of app...

We present results on electrically driven nanobeam photonic crystal cavities formed out of a lateral p-i-n junction in gallium arsenide. Despite their small conducting dimensions, nanobeams have robust electrical properties with high current densities possible at low drive powers. Much like their two-dimensional counterparts, the nanobeam cavities exhibit bright electroluminescence at room temp...

Patients and methods In this pilot study we report 20 children with jSpA, diagnosed based on both ESSG and ILAR criteria, which we treated, in addition to standard NSAID therapy, with LLLT. We used gallium-aluminium-arsenide (Ga-Al-As) continued laser (Iskra Medical, Slovenia). The usual location of treatment was AC joints, infrapatelar and/or Achilles' tendon insertions. The effects of therapy...

Structural transformation in gallium arsenide nanocrystals under pressure is studied using molecular-dynamics simulations on parallel computers. It is found that the transformation from fourfold to sixfold coordination is nucleated on the nanocrystal surface and proceeds inwards with increasing pressure. Inequivalent nucleation of the high-pressure phase at different sites leads to inhomogeneou...

A comprehensive physical model is used in a twodimensional numerical simulation of highly doped gallium arsenide MESFETs. Particular attention is paid to the formulation of the numerical schemes and boundary conditions to ensure accurate modelling. A specially formulated current continuity finite difference equation is used, which produces stable, accurate and efficient solutions, even at carri...