Liquid Crystal Based Polarization Gratings for Spectro-Polarimetric Applications

Two approaches to produce near-ideal Cycloidal Optical Axis Gratings (OAGs) based on liquid crystalline materials have been proposed. Both methods rely on polarization holograms recorded on the photoaligning substrates for liquid crystal devices. In the first case, a nematic LC layer, made of low molar mass mesogens, is confined between two parallel substrates, both imposing spatially periodic planar alignment. In the second case, a reactive mesogen (RM) is coated on a single aligning substrate. The unique polarization properties of the OAG have been exploited for the development of a photopolarimeter and a real time and artifact-free circular dichroism spectrograph.