Photochromic gratings in photorefractive materials.

The steady-state and dynamic behavior of absorption and phase gratings in semi-insulating GaAs and InP have been studied by four-wave mixing. These measurements permit independent study of the space-charge-field screening kinetics and free-carrier recombination kinetics in these materials. The study is important both for the design of optimized materials for photorefractive applications and for the characterization of the defect electronc structure in these materials.