研究了用于测量两束光频差的时间延迟激光感生双光栅的频谱分辨率，确定了当泵浦光具有高斯线型时四波混频信号的产生条件，此条件通过在可调谐的窄带激光和宽带激光间的拍频实验得到证实。 The spectral resolution of the time-delayed laser-induced double grating for measuring the frequency difference between two beams was studied, and the condition for generating the four-wave mixing signal when the pump light has a Gaussian line type was determined. The beat frequency experiment between narrow-band laser and wide-band laser was confirmed.