Optical nonlinearity and bistability in liquid crystals

Abstract

Molecular reorientation and laser heating induced by an optical field can yield significant changes in the refractive indices in a nematic liquid crystal. A c.w. laser beam is intense enough to induce a phase retardation much larger than 2pi in a nematic film less than 100 pm thick. Optical bistability in such a film sandwiched between mirrors can be readily observed. Coupling between the two mechanisms for induced refractive indices can lead to interesting results in the bistable operation.