Optical nonlinearities at transient quenching of EL2 defect at room temperature

We investigate numerically the nonequilibrium dynamics of carriers and inte rnal space charge field during the photoquenching of metastable defect EL2 by short pulse of light interference field. Simulation of free carrier, pho torefractive, and absorptive optical nonlinearities at various illumination intensities allowed us to reveal conditions for the efficient transient qu enching of EL2 at room temperature. Contribution of this effect to light di ffraction and absorption is in favorable agreement with experimental data o f degenerate four-wave mixing at 1.06 mu m wavelength in LEC and Bridgeman- grown GaAs crystals using 10-ns duration YAG:Nd laser pulses. (C) 1999 Else vier Science B.V. All rights reserved.