Optical evaluation of Cytop, an amorphous fluoropolymer, in the terahertz frequency across a wide temperature range

Cytop is an amorphous fluororesin that has been attracting attention from researchers due to its potential application as an optical thin film coating for nonlinear optical (NLO) crystals in terahertz (THz) wave generation. In this study, we confirmed the suitability of Cytop as a coating material by measuring its optical parameters in the THz frequency band using THz time domain spectroscopy over a wide range of temperatures. Furthermore, as Cytop has a refractive index of about 1.35 in the light wave band, we also investigated its potential as an anti-reflection coating material for NLO crystals used as THz sources. (C) 2019 The Japan Society of Applied Physics