以惠更斯-菲涅尔衍射公式为基础，推导了猫眼系统的回波光场，并以二维光栅作为凝视光电成像系统的焦平面器件进行理论计算和实验验证.分析了光阑孔径对回波图像与焦平面器件调制之间相关性及空间截止频率对猫眼回波的影响.结果表明：随着光阑孔径的减小，回波图像信息减少，与焦平面上光斑的相关性降低；随着光阑孔径的增大，光栅干涉形成的次级光斑逐渐出现在回波图像中，回波图像也由于各级光斑的干涉变得复杂，对应的空间频谱变化反映了各级光斑的交叠情况.该研究对利用回波特征用于凝视光电成像侦察设备实施激光主动探测具有实际应用价值.

The echo-wave was deduced based on the Huygens-Fresnel diffraction formula. The numerical results with the two-dimensional grating as focal plane device of staring photoelectric imaging system were verified experimentally. The impact of aperture size on the correlation between the echo image and the modulation of focal plane device was analyzed, and the influence of the cut-off frequency on the echo-wave was also discussed. With the size of aperture decreasing, the information of echo wave decreases, and the correlation also decreases. What′s more, with the aperture size increasing, more and more diffraction spots from the grating appear in the echo-wave image which shows complex pattern because of the interference between the spots. The spatial frequency of the pattern reflects the overlapping of the diffraction spot. The study of echo characteristics has practical application value for laser active detection on photoelectric reconnaissance equipment.