Optical properties of broad stopband of a chiral smectic liquid crystal at highly oblique incidence

Abstract

The optical properties of stopbands of a ferroelectric liquid crystal (FLC) in a chiral smectic C phase are investigated experimentally and theoretically. Chiral smectic and cholesteric liquid crystals are regarded as pseudo photonic crystals. They exhibit Bragg reflections corresponding to half- and full-pitch bands. The characteristics of the Bragg reflections at oblique incidence are discussed on the basis of numerical calculations. The full-pitch band of an FLC becomes deeper and wider at highly oblique incidence. Using this characteristic, we demonstrated an FLC stopband with independently tunable wavelength and bandwidth by controlling the temperature and incident angle, respectively.