Diffraction of cholesteric liquid crystal gratings probed by monochromatic light from 450 to 750 nm

We investigated both theoretically and experimentally the diffraction property of cholesteric liquid crystals (CLCs) in the configuration of transmission grating. The CLCs are treated as birefringent index gratings whose diffraction property is strongly dependent on the polarization state of the incident beam. In our experimental studies, the CLC index gratings are constructed by applying an electric voltage to liquid crystal cell. The grating is probed by a monochromatic light in spectral range from 450 to 750 nm and the measured diffraction efficiency approximately agrees with the theoretical predictions. The dependence of polarization and wavelength of polarized monochromatic light may possibly lead to a light switch in optical communication system.