Transient behavior of the photorefractive space-charge field

The transient behavior of the fundamental amplitude of the photorefractive space-charge field is derived without restrictions within the band transport model. The two-wave mixing pulse excitation regime is simulated in different ranges of the main parameters, especially in the region where the nonlinear processes become important. The formation and decay of the field are analyzed, and for different ranges of the excitation parameters the corresponding behaviors are predicted. Features of the field such as the nonlinear decay of the photorefractive field at high-writing pulses, its oscillatory behavior when an external field is applied, and the dependence of its formation and decay time on the grating spacing are studied.