The method, by using photoconductive semiconductor switch to generate the offset voltage for terahertz time-domain spectrum system, was adopted to improve system's performance. Based on the analysis of the terahertz wave's generation mechanism by photoconductive semiconductor switch, the problems within the current terahertz time-domain spectrum system were fully examined, the solutions to solve the contradiction between the mechanic noise induced by chopper and the photoconductive antenna's offset voltage, were discussed. Last, after testing the characteristic parameters of photoconductive semiconductor switch, a scenario which took advantage of high-voltage direct current source, photoconductive semiconductor switch, and nanosecond laser to generate 0 to 9 kV offset voltage without mechanic noise, was put forward to level up the amplitude of the offset voltage to improve terahertz time-domain spectrum system.%利用光导开关产生脉冲偏置电压的方式改进了基于光电导天线的太赫兹时域光谱系统.在分析光电导天线产生THz波原理的基础上,重点研究了目前基于光电导天线的太赫兹时域光谱系统存在的问题,探讨了解决斩波器引起的机械噪声和光电导天线脉冲偏置电压之间矛盾的途径.最后,通过对光导开关的特性测试,提出了利用高压直流电源、光导开关和纳秒激光器产生0～9 kV脉冲偏置电压消除机械噪声、提高脉冲偏置电压幅度的方法,改进了太赫兹时域光谱系统.
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