We will describe optical and electrical effects in photorefractive materials- in semiconductors and semiconductor-ferroelectric crystals. Double-functional (optical and electrical) interferometer was realized using holographic recording of dynamic gratings in the semiconductor crystal of CdTe: V. Two mechanisms of holographic phase grating recording is considered: electro-optic effect (relatively slow, in microsecond) and free-carrier gratings {Drude-Lorentz nonlinearity, fast response in nanoseconds). Fast optical response, based on Drude-Lorentz nonlinearity (also called plasma nonlinearity) play essential role in the surface- plasmon resonance phenomena.