采用飞秒激光激励光导开关能够产生脉宽皮秒甚至亚皮秒级的太赫兹脉冲,近年来,这项技术成为校准宽带示波器上升时间的有效手段。以低温生长砷化镓(LT-GaAs)为光导开关的基底,在飞秒激光激励下产生太赫兹脉冲,经共面波导传输,通过微波探针耦合为1.85mm同轴输出,然后利用带宽70GHz的取样示波器对其半幅度宽度进行测量。实验获得太赫兹脉冲的半幅度宽度(FWHM)约为7.4ps。 The use of femtosecond laser-activated photoconductive switches to generate pulses of picosecond or even sub-picosecond terahertz pulses has become an effective means of calibrating the rise time of broadband oscilloscopes in recent years. The low-temperature growth of gallium arsenide (GaAs GaAs) as the base of the photoconductive switch, in the femtosecond laser excitation generated by the terahertz pulse, the coplanar waveguide transmission through the microwave probe coupled to 1.85mm coaxial output, and then use the bandwidth of 70GHz The sampling oscilloscope measures its half width. The half width width (FWHM) of the experimental THz pulse is about 7.4 ps.