Frequency response of terahertz electro-optic sampling detection technology with thin GaSe crystal

GaSe crystal has good applications in the broadband terahertz pulse generation and electro-optic sampling detection technology. In this paper, the frequency responses of GaSe crystal with different thicknesses in the electro-optic sampling (EOS) detection technology are investigated based on the numerical calculations. Then, the pulse distortions of terahertz induced by the EOS detection technology with thin GaSe crystal are investigated. It is found that the lower the central frequency of the terahertz pulse is, the less the distortion is. When the central frequency of terahertz pulse is higher than 4 THz, the pulse distortions, including the frequency shift and the bandwidth changing, are greatly obvious. Both induced by the EOS technology with different thickness of GaSe crystal are also given in detail. This work provides a good reference to evaluate the performance of EOS detection technology with thin GaSe crystal in the broadband terahertz science and technology.