Photoinduced scattering of light by fluctuations of photoelectric parameters of a medium

A study is made of the scattering of light by photorefractive media. It is shown that the main reasons for a strong photoinduced light scattering are small-scale (of the order of one optical wavelength) spatial fluctuations of the photogalvanic coefficient and of the parameters of the electrical conductivity, as well as spontaneously formed noise phase holograms. Reported experiments show that in the case of LiNbO₃:Fe crystals the leading role is played by electrical conductivity inhomogeneities of the photogalvanic origin. A simple model of such inhomogeneities is suggested and it is used to provide a satisfactory description of the characteristic features of a steady-state indicatrix of photoinduced light scattering corresponding to different polarizations of the pump and scattered radiation.