Effect of Light Polarization on the Optical Freedericksz Transition in an Oligothiophene-Doped Liquid Crystal

Abstract

We studied the optical Freedericksz transition (OFT) in an oligothiophene-doped liquid crystal (LC) with linearly polarized and unpolarized laser as the irradiation light. In both cases, OFT occurred at the light intensity of only a few W/cm^2. It was found that the light intensity required for reorientation decreased with an increase in the incident angle for extraordinarily polarized incident light, while a contrary variation tendency was found for ordinarily polarized light. Based on these results and the birefringence of LCs, we evaluated the OFT behavior induced by unpolarized light and proposed a possible way to control the azimuthal angle of the LC alignment.