Polarization holographic techniques: a method to produce diffractive devices in polymer dispersed liquid crystals

We report a Study of holographic gratings recorded by exposing a homogeneous mixture of prepolymer and liquid crystal to polarization light patterns. The method is based on the alignment control of the liquid crystal domains during the photo-induced polymerization process. In contrast, the usual methods to write diffraction gratings in polymer dispersed liquid crystals are based on an intensity holographic technique that controls the polymerization process. The polarization patterns here are made using different geometries: in particular we report results from exposure to polarization patterns realized by the superposition of two waves having orthogonal linear polarizations. or two waves having opposite circular polarizations. Analyses of the recorded gratings are reported.