Abstract
The moving grating method was applied to a photorefractive Bi12SiO20 crystal in order to enhance the light amplification factor γ0 in the two-wave mixing process and the reflectivity R of the phase conjugate wave in the four-wave mixing process. It was found that γ0 and R exhibited maximum values when the interference pattern moved inside the Bi12SiO20 crystal at an optimum velocity. We achieved 65% reflectivity of the phase conjugate wave at that velocity. The response time of the photoinduced refractive index grating was determined with varying incident beam intensity, external electric field and grating spacing.