Properties of two-component nematic liquid crystal mixtures in the range of 0.3–3.0 THz

Abstract

In this work, we present the results of terahertz measurements of five nematic liquid crystal materials. Optical properties like refractive indices, birefringence and absorption coefficients of liquid crystals (LCs) for ordinary and extraordinary polarisation were compared. The aim of this study was to check the impact of the structure of LC molecules on above properties. The compounds with different core structure and various number of laterally substituted fluorine atoms were chosen. A standard terahertz Time-Domain Spectrometer to measurements from 0.3 THz to 3 THz was used.

High-birefringence nematic liquid crystal for broadband THz applications

“…In recent years, the characterisation at THz frequencies of different commercially available or home-made LCs has drawn increasing attention. [15][16][17][18][19] Compared with the visible region, LCs typically exhibit relatively small birefringence and high loss due to the requirement of much larger device thickness for THz radiation, [20,21] leading to disadvantages in the switching on/off time of LCs-based devices given that it is proportional to the square of the effective LCs layer thickness. Thus, high birefringence and low-loss LCs could facilitate fast, efficient and compact THz applications.…”