Optical and Dielectrical Properties of Opal Water Content Determination Using Terahertz Time-Domain Spectroscopy.

The optical and dielectric properties of opals with different water contents were investigated using terahertz time-domain spectroscopy. The refractive indices and absorption coefficients showed different trends due to the different water contents. The effective medium theory was used to extract the intrinsic dielectric permittivity of opal from opal-polytetrafluoroethylene mixtures.

Effect of crystal-water on the optical and dielectric characteristics of calcium sulfate in the THz band.

The effect of crystal-water contents on the optical properties and dielectric characteristics of calcium sulfate in the THz band is investigated. The complex dielectric constant and conductivity are analyzed using the Drude-Smith model. The refractive index and absorption coefficient are linearly increased with the content of crystal-water, and the corresponding linear fitting lines of R over 0.