ABSTRACT
Birefringence and extinction coefficients of positive nematic liquid crystal (NLC) MLC-2142 and negative NLC BHR28000-400 are measured by terahertz time-domain spectroscopy system (THz-TDS). Frequency ranging from 0.1 to 0.6 THz, the birefringence of positive NLC MLC-2142 increases with the increase of frequency, and keeps larger than 0.23, which exhibits application potential in tunable broadband LC THz device where a large birefringence is required. In contrast, the birefringence of BHR28000-400 decreases with the increased frequency, which shows a completely different optical property from the positive NLC. The extinction coefficient of the above two kinds of liquid crystals are also investigated.
Graphical Abstract
Disclosure statement
No potential conflict of interest was reported by the authors.