在分析单个衰减片、一对类V字型排列的衰减片、一对平行型排列的衰减片光斑分裂特征的基础上,给出N个衰减片使用时,光斑能量分裂、分裂光斑各级中心间距及重叠部分的表征方法。探寻出2种有效的解决方案,并给出详细的设计方法、使用方法。研究结果表明:存在最优入射角,可使各级杂斑间距最大,对于折射率为1.4~1.7的常用的衰减片介质材料,最优入射角为48°~50°;充分利用类V字型、平行型组合衰减片的光路传输特点,合理摆放衰减片、科学使用光阑,可有效去除各级杂斑,获得理想的单一主光斑。

Based on the analysis of the characteristics of the beam splitting when a laser beam passes through a single attenuator, a pair of attenuators with V-type and parallel arrangement, methods are given for the characterization of the beam energy splitting, beam center spacing, and their overlapping parts for N-attenuators. Two effective solutions are explored, and details of the design and application methods are presented. The results show that there is an optimal incidence angle that can maximize the spacing of all levels of speckles. For common attenuating materials with a refractive index in the range of 1.4 to 1.7, the optimal incidence angle is in the range of 48° and 50°. Therefore, by making full use of the optical transmission characteristics of attenuators with V-shaped and parallel-shaped arrangement, rationally placing the attenuators, and using the beam stop scientifically, speckles at all levels can be effectively removed and an ideal single beam spot can be obtained.