Terahertz spectroscopy was used to study the sintering process of traditional ceramic by scanning sample with different final temperatures (from 100-1450°C). Absorption coefficient (α) and refractive index (<i>n</i>) were obtained with different final temperatures. The sintering process was divided into four stages on the basis of α and n, which characterized the ceramic sintering process well. The results coincide with the actual situation. Therefore, THz-TDS represents a promising technique to monitor the synthesis process of materials.
Optical properties of the group components in crude oil were studied using terahertz time-domain spectroscopy (THz-TDS) under nitrogen environment at ambient temperature. The group composition of crude oil from different oil fields were analyzed on the basis of terahertz spectra. Both time delay and amplitude of terahertz wave were modulated in accordance with group composition. The features of terahertz spectra which contain information from different parts of the crude oil group composition can be qualitatively analyzed to detect the group components of the crude oil.