Title :
Picosecond photorefractive and free-carrier transient energy transfer in GaAs at 1 mu m
Author :
Smirl, Arthur L. ; Valley, George C. ; Bohnert, Klaus M. ; Boggess, Thomas F., Jr.
Author_Institution :
Hughes Res. Lab., Malibu, CA, USA
Abstract :
The strength, formation, and decay of photorefractive and free-carrier gratings written in GaAs by 43-ps pulses at a wavelength of 1 mu m are investigated using picosecond-time-resolved two-beam coupling, transient grating, and degenerate-four-wave-mixing techniques. Photorefractive weak-beam gains of a few percent are measured at fluences of a few pJ/ mu m/sup 2/ (0.1 mJ/cm/sup 2/), and gain from transient energy transfer is observed at fluences larger than approximately 10 mJ/cm/sup 2/ in the beam-coupling experiments. The roles of saturation and two-photon absorption in determining the final electron, hole, and ionized-donor populations and the roles of drift and diffusion in determining the quasi-steady-state photorefractive and free-carrier index modulations are discussed.<>
Keywords :
III-V semiconductors; diffraction gratings; gallium arsenide; nonlinear optics; optical phase conjugation; optical saturation; photorefractive effect; two-photon spectra; 1 micron; 43 ps; GaAs; III-V semiconductor; degenerate-four-wave-mixing; diffusion; drift; electron population; free-carrier gratings; free-carrier index modulations; free-carrier transient energy transfer; gain; hole population; ionized-donor populations; photorefractive gratings; picosecond-time-resolved two-beam coupling; saturation; transient grating; two-photon absorption; weak-beam gains; Absorption; Charge carrier processes; Energy exchange; Energy measurement; Gain measurement; Gallium arsenide; Gratings; Photorefractive effect; Photorefractive materials; Wavelength measurement;
Journal_Title :
Quantum Electronics, IEEE Journal of
