Analysis of diffraction in periodic liquid crystals: the optics of the chiral smectic C phase

A method for analyzing diffraction properties of periodic liquid crystals is presented that uses the previous theory for anisotropic dielectric gratings [ J. Opt. Soc. Am.73, 901 ( 1983)]. The method applies to any type of periodic liquid-crystal structure with arbitrary orientation of the helical axes. As an example of the present analysis, both forward and backward diffraction properties of a chiral smectic C phase are given for the incidence of linearly polarized and circularly polarized waves. An approximate two-wave analysis is also derived and is compared with the rigorous results.