Terahertz properties of fluorinated liquid crystals

Abstract

In this article, optical properties of four fluoro-substituted 4-propyl-4′-[(4-ethylphenyl)ethynyl] biphenyls and liquid crystal mixture A are presented in the terahertz (THz) range. Birefringence, refractive indices and absorption coefficients for ordinary and extraordinary ray of liquid crystals are described in the range of 0.3 to 3.0 THz. It shows that the measured parameters are dependent on the number and placement of fluorine atoms in the molecules. Measurements have been performed using time-pulsed spectroscopy.

Keywords:

• terahertz
• liquid crystal
• spectroscopy
• absorption
• birefringence

Acknowledgements

The authors thank Norbert Palka for providing THz spectrometer and valuable guidance. This work was supported by the Polish Ministry of Sciences and Higher Education, No. O R00 0144 12 and HKUST grant CERG 612310.