Accession Number : ADA316164
Title : Optics with Semiconductors: Ultrafast Physics for Devices.
Descriptive Note : Final rept. 1 Jun 91-30 Nov 92,
Corporate Author : ROCHESTER UNIV NY DEPT OF ELECTRICAL ENGINEERING
Personal Author(s) : Fauchet, Philippe M.
PDF Url : ADA316164
Report Date : 09 SEP 1996
Pagination or Media Count : 7
Abstract : We have established the exact nature of the various scattering processes between carriers and the many body effects that produce large nonlinearities near the bandedge of direct gap Ill-V semiconductors. The femtosecond optical nonlinearities near the bandedge of GaAs have been investigated after injection of very hot carriers with 2 eV photons. Instantaneous changes of refractive index and absorption coefficient have been found to be consistent with bandgap renormalization and screening of the Coulomb interactions. The combined effects of bandfilling, bandgap renormalization, plasma screening of the Coulomb interactions. and free carrier absorption leads to an optical response that may be exploited in device applications. At high injected densities, the dynamics of gain near the bandedge has been established. It is controlled by electron-electron and electron-hole scattering, and numbers for these effects have been obtained. The initial scattering of the hot carriers has been investigated by hole burning experiments in intrinsic p-type and n-type GaAs. In some cases, a very short scattering time (<25 fs) has been observed due to emission of coupled plasmon-phonon modes.
Descriptors : *ELECTROOPTICS, *SEMICONDUCTOR DEVICES, GALLIUM ARSENIDES, ELECTRON SCATTERING, CHARGE CARRIERS, HOLES(ELECTRON DEFICIENCIES), NONLINEAR OPTICS, N TYPE SEMICONDUCTORS, SHORT PULSES, ABSORPTION COEFFICIENTS.
Subject Categories : Electrooptical and Optoelectronic Devices
Distribution Statement : APPROVED FOR PUBLIC RELEASE