Optical constants of some liquid crystals measured by terahertz time-domain spectroscopy

Terahertz spectroscopy contains rich physical, chemical, and structural information of the materials, and one unique attribute of terahertz is their ability to sensitively measure the induced molecular dipole moments of many liquid crystals. In this paper, the transmission spectra of several liquid crystals 5CB, TEB300, LC203000 LCs were measured by THz time-domain spectroscopy technique and free-space electro-optic sampling method. The refractive indexes of the mentioned liquid crystals in the THz range are calculated. Furthermore, the optical constants are compared and analyzed, expecting to fill the spectrum gap of liquid crystals in the THz range and provide the experimental and theoretical foundation for the application of liquid crystals.