Electrically controlled depolarization of light by use of liquid crystal cells

摘要

In this paper we present a new method of depolarization of light by using an electrically-controlled liquid crystal rotator in combination with a solid-state crystal with high birefringence. In general, anisotropic crystals depolarize partially temporary coherent light depending on their birefringence and path length of the light passing through them as well as on the azimuth of the optical beam i.e. the angle between the electric vector of the light wave and the birefringence axis of the crystal. Electrically-controlled liquid crystal rotator is a useful tool to introduce changes in azimuth and in the same to control depolarization of the light passing through the crystal placed behind the polarization rotator. Some experimental results of degree of polarization measurements for different light sources as a superluminescent diode and a laser diode are presented. Totally depolarization of light was achieved for the superluminescent diode and lithium niobiate crystal with the liquid crystal electrically controlled rotator.