Optical reorientation in cholesteric nematic mixtures

Abstract

The optical Fréedericksz transition for linearly polarized light at normal incidence is studied in mixtures of nematic E7 and cholesteric C15 in cells coated for homeotropic alignment. The reorientation process is found to be dramatically different from the case of pure nematic samples showing the phenomenon of optical phase locking and large hysteresis. These effects are ascribed to the occurrence of self-induced stimulated light scattering, which does not occur in pure nematics.