Tunable Amphoteric Refraction in Semiordered Nematics

Abstract

This paper demonstrates amphoteric refraction in semiordered uniaxial liquid crystal (LC) and reveals the impact of the LC ordering degree and the director axis on the refraction. In particular, it elaborates more on the negative refraction and how a variation in the order parameter will affect the negatively refracted extraordinary ray, even when the director axis is undeformed. This study of the negative refraction with explicit treatment of the ordering degree is significant. It helps in tracking the LC profile deformation in LC based sensors when the molecular degree of ordering is distorted, with or without the influence of temperature. The explicit treatment of the order parameter is critical when trying to differentiate between a change in the alignment (average director deformation) and a degradation of the alignment (loss in complete uniaxial structure).