Polarization Bistability in Cholesteric Liquid Crystals

Abstract

Cholesteric liquid crystals possess an intrinsic helical structure which enables them to selectively reflect circularly polarized light if the wavelength of the light matches the pitch of the helix. We recently showed that intense light can change the pitch of the cholesteric and lead to a bistable reflection characteristic for wavelengths in the Bragg regime1. We have now extended our analysis to the regime of wavelengths much shorter than the helix pitch. In this limit (known as the Mauguin limit) there are no Bragg reflections and, except for normal dielectric reflections, an incident wave will enjoy 100% transmission. Since the cholesteric represents a twisted, birefringent medium, the polarization state of the light will evolve periodically in space.