The birefringence and extinction coefficient of positive and negative liquid crystals in the terahertz range |
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| Authors: | Qi Fu Liu Shao Xian Li Zhen Tian |
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| Affiliation: | 1. Department of Electrical &2. Electronic Engineering, Southern University of Science and Technology, Shenzhen, China;3. Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China |
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| 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. |
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| Keywords: | Positive liquid crystals negative liquid crystals birefringence THz |
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