Optical diffraction in chiral smectic-Cliquid crystals

Abstract
We report a study on the optical diffraction for light propagation perpendicular to the twist axis in the chiral smectic-C liquid crystal. In this phase grating mode, we find very unusual intensity and polarization features in the diffraction pattern. These observed features can be explained by invoking the theory of anisotropic gratings which takes into account the internal diffractions.