Temperature dependence of optical parameters of a single crystal MnBOCl in the THz frequency range.

The dependence of optical properties of crystal on different temperatures within the terahertz frequency band has been investigated. By employing terahertz time-domain spectroscopy, the refractive index, absorption coefficient, and dielectric constant of the crystal were obtained. Results indicate that within the frequency range from 0.4 to 0.8 THz, both the refractive index and absorption coefficient increase steadily with temperature. While significant fluctuations are observed in the frequency from 1.2 to1.7 THz. This is mainly attributed to the polarizability of the ion groups [] and [-], affected by the ambient temperature and the terahertz frequency. This research reveals the absorption mechanism of polar mineral materials in the terahertz frequency band and provides, to our knowledge. new insights into polar material application within the THz regime.