Optimized seeded Bridgman growth and temperature dependent THz optical properties of LiInS2 crystals

High quality and large size nonlinear optical LiInS2 (LIS) crystals were successfully grown by the optimized seeded Bridgman method. And the optical properties and carrier dynamics of LIS in the THz range were investigated by THz time-domain spectroscopy (THz-TDS) in the temperature range of 20–300 K for the first time. The refractive index and absorption coefficients present obvious temperature dependent behavior. A distinct absorption peak was observed at around 1.68 THz, which can be attributed to the vibration of In–S bonds revealed by Raman spectroscopy analysis. And the carrier concentration, mobility and scattering rate also show obvious temperature dependent behavior. These results will provide further understanding of the optical properties of LIS crystals and a perspective for future applications of LIS crystals in THz technology.