Slow-light birefringence and high precision polarization interferometry in liquid crystal light-valves

Abstract

Liquid crystals are characterized by a strong anisotropy of their physical properties, which is at the origin of their high birefringence. By performing two-wave mixing experiments in a liquid crystal light-valve, we show that the anisotropic nature of the beam coupling occurring in the liquid crystal layer leads to a slow-light birefringence phenomenon, that is, orthogonal polarization states of the input pulse travel at very different group velocities. Such a slow-light birefringence effect comports a large difference in the group index for the ordinary and the extraordinary wave. The resulting high contrast of the group index can be exploited for realizing a common-path polarization interferometer working at enhanced sensitivity, where very small phase variations can be efficiently detected.