Intensity dependence of the grating formation in photorefractive BaTiO3

The interference pattern of light waves creates a refractive index modulation in photorefractive media. This process is relatively well described by the theory (Kukhtarev equations) bur deviations are found. Therefore, experimental methods are used in order to characterize the processes. The influence of the absolute intensity as well as of the intensity ratio of the interfering waves on the refractive index modulation are studied in a two-wave mixing arrangement. In particular, for the dependence on the absolute intensity the interesting relation Delta n = f(I-abs) proportional to I-abs(alpha) Was found that was not predicted by the theory. Nevertheless, this experimental approximation can be used in calculation in order to minimize the error.