Photoinduced Polarization-Independent Refractive Index Modulation Using Azo-Dye Doped Liquid Crystal

We demonstrate polarization-independent refractive index modulation using an azo-dye doped liquid crystal (azo-LC). The azo-LC is aligned homeotropically and irradiated by ultraviolet (UV) light resulting in optically induced nematic-isotropic phase transition. This homeotropic-isotropic transition causes a refractive index modulation, which is independent of polarization for light travelling perpendicularly to the azo-LC layer. In order to evaluate the amount of the modulation, we fabricated an etalon which contains a homeotropically aligned azo-LC layer between the mirrors, and observed the polarization-independent refractive index modulation by 0.03.