基于太赫时域光谱系统的应力双折射现象研究

In this paper, THz time domain spectroscopy (THz-TDS) system is used to study the stress-optical effect of polytetrafluoroethylene (PTFE), which is a typical optically opqaue materials. At first, the traditional THz-TDS system is updated so that it can control and sense the polariztion of the embed THz wave. The THz wave penetrates the PTFE specimen with mechanical loading. At the same time, the strain guages are used to measure the stress state undergone by the specimen. Then, fourier transform are applied on the captured THz wave, and the phase datum are analysed. The results shows that there is a linear relation between the applied stress and the phase delays of the penatrated THz wave. These results proved that the traditional stress-optical law is still right in the THz regime. It can be used to determine the interior stress of opticall opaque materials.