THz Time-Domain Spectroscopy of Cesium Iodide

摘要

The optical properties of Cesium Iodide (CsI) in the frequency range from 0.1 to 2.0 THz were studied by employing THz time-domain spectroscopy. The CsI samples were synthesized using CsI powder that was pressed into 2 mm thick pellets. The obtained time-domain data were transformed into the frequency domain using Fourier Transforms, and then analyzing the respective phase and amplitude spectra, the refractive index (RI) and the absorption constant of CsI were deduced. The RI of CsI is seen to increase from 2.55 to 3.15 as the frequency increases from 0.15 to 1.4 THz. For frequencies above 1.4 THz, the data was unusable due to the increased absorption. The empirical Sellmeier equation was used to fit the frequency-dependent RI and to determine the absorption wavelength λ_1.