从分析高斯本振光和爱里信号回波互相干函数 (或外差量子效率 )一阶统计量入手 ,推导出CO2 激光脉冲外差探测振幅、位相和波矢空间夹角匹配条件 ,其外差量子效率的最大理论值为 0 82。在离焦失准状态下 (即球像差 ) ,两束光的位相差主要由高斯本振光波前弯曲决定 ,并因此导致外差量子效率的降低。 Starting with the analysis of the first-order statistics of the mutual function (or heterodyne quantum efficiency) of Gaussian local oscillator light and Aryi signal echo, the matching conditions of amplitude, phase and wave vector space of CO2 laser pulse heterodyne detection are deduced. The maximum theoretical value of the difference quantum efficiency is 0 82. In the case of out-of-focus misalignment (ie, spherical aberration), the phase difference between the two beams is mainly determined by the Gaussian local oscillation light wavefront curvature, and thus results in a decrease in heterodyne quantum efficiency.