Experimental Study on Higher Order Reflection by Monodomain Cholesteric Liquid Crystals

Abstract

Reflection spectra have been measured in the spectral region of the second and the third order selective reflections for monodomain cholesterics of various cell thicknesses at various angles of incidence. Thicker cells give rise to higher reflectance at larger angles of incidence. The second order reflection region consists of three bands which show characteristic polarization correlation: The central band is a total reflection band, where incident light of any polarization is reflected. The reflected light is a polarized when it polarized light is incident and vice versa. Contrary to the central band, two side bands are selectively reflected; σ(π) polarized light is reflected in the longer (shorter) wavelength band retaining its polarization. The third order reflection bands observed for the first time have been found to give the same polarization characteristics as that of the second order reflection bands.