Photoinduced light scattering in crystals with a nonlocal response

A theory of Rayleigh light scattering is developed for photorefractive media of the strontium barium niobate (SBN) type with a diffusion mechanism of formation of optical inhomogeneities. The photoinduced increase in the scattering intensity is considered to be the result of spontaneous recording of noise phase holograms in an inhomogeneous crystal. The angular structure and the time dependence of this scattering intensity are determined. It is shown that as a result of holographic effects the scattering indicatrix may be essentially asymmetric. Theoretical calculations made for an SBN crystal show good agreement with the experimental results.