Angular Dependence of Blue Phase Selective Reflection in the Electric Field

Abstract

The angular dependence of the selective reflection peaks has been investigated for BP1 and BP2 as well as for non-cubic BP-structures occurring in the electric field. Although at normal light incidence the ratios of the wavelengths of reflection bands are known to fit in a Bragg condition, we found that the angular dependence behaves non-Bragg-like, i.e. certain reflection peaks are shifted to longer wavelengths with increasing angle of reflection. The angular dependence can be used to distinguish between the effects of deformation, reorientation and phase transitions occurring under the influence of the electric field.