Characterization of stress birefringence of organic silica gel by terahertz time domain spectroscopy

The stress optical coefficient of material is an important parameter to measure the internal stress of material by photoelastic method. In this paper, the polarization state terahertz time domain spectroscopy system is built, and the stress birefringence of organic silica gel is measured, so as to obtain the stress optical coefficient in THz region, which provides a basis for the calculation of internal stress. This method verifies the feasibility of the stress optical property law in THz band, and provides a new method for characterizing the internal stress of non transparent materials.