Electro-optical phenomena due to influence of light beams on material parameters of liquid crystals

Modulation of material parameters of liquid crystals (LC) due to absorption of light beams allows to control the reorientation of the LC under the inf luence of ac electric fields. Particularly, it makes possible recording of photorefractive-like orientation gratings. Such gratings are phase shifted with respect to the pattern pf interfering light beams. The material and ex ternal parameters determine the magnitude of the shift. These photorefracti ve-like phase shifted gratings are stationary, and no diffusion processes a re involved in their build-up.