传统的光学镜头探测主要基于回波强度(猫眼效应)来实现,但对于微型镜头而言,反射回波中存在明显的衍射现象,因此对微型镜头光阑衍射效应的研究成为一个重要的研究方向。基于角谱衍射理论,研究了微型镜头对辐照激光的空间调制特性,推导了回波光场分布的公式;仿真研究了探测距离、入射角度和光阑直径对衍射光场分布的影响,以及不同光阑直径时的最大可探测入射角,并利用搭建的激光主动探测系统对回波衍射现象进行了探测。结果表明,实际探测的衍射图样与仿真图样吻合得较好,所提理论能够准确地预测微型镜头探测回波的衍射现象。

The traditional optical lens detection is mainly based on echo intensity (cat-eye effect). However, there are obvious diffraction phenomena in reflection echoes for micro-lens. Thus, it is important to investigate the diaphragm diffraction effect of micro-lens. Based on the theory of angular spectral diffraction, we study the spatial modulation characteristics of micro-lens for irradiated laser, and deduce the equation for optical field distribution of echo signal. The influences of the detection distance, incident angle, and diaphragm diameter on the diffraction optical field distribution are simulated, as well as the maximum detectable incident angle under the condition of different diaphragm diameters. Moreover, the diffraction phenomena are detected using the constructed active laser detection system. The results indicate that the diffraction patterns observed from the experiment match well with the simulated patterns. The theory, developed in this article, is proved to be qualified to predict diffraction profiles of micro-lens' echo signal to an extraordinary degree.The theory can accurately predict diffraction phenomena in echoes for micro-lens.