Textural and electro-optical study of cholesteric liquid crystal for light shutter

Abstract

Cholesteric Liquid Crystal (ChLC) exhibits one dimensional periodicity and is widely studied for electro-optical switching devices such as light shutters. This paper demonstrates the textural and electro-optical characteristics of ChLC. In this experiment ChLC mixture was prepared with nematic LC and a chiral dopant R1011 having helical twisting power (HTP) 25 ?m?1. The switching between a transparent planar (P) state to an opaque focal conic (FC) state and vice versa was studied for light shutter application. Further, ChLC exhibits a stable transparent and opaque state with well aligned P and FC textures, while the applied field is turned off. Moreover, the effect of 0.4wt.% of dichroic dye on electro-optical characteristics of ChLC was investigated. Results reveal that the switching voltage from P to FC state reduced significantly with the addition of dichroic dye, however, the isotropic temperature of dye doped ChLC found to be lowered in comparison with ChLC mixture.