为了大功率激光设备工作时, 减小高斯光束束腰半径外低能量所产生的边缘效应, 避免出现毛边、搭接痕迹明显等问题, 需要对它进行光束整形设计。针对大功率激光光源特性(输出平均光功率为500 W, 脉冲宽度为130~160 ns, 重复频率为20~50 kHz, 波长为1 064 nm, 功率调节范围为10%~100%), 为了减小系统的复杂性, 提高激光能量的利用率, 采用伽利略式非球面透镜整形系统进行参数优化; 选取平顶洛伦兹模型为物理模型, 根据能量守恒定律求得入射光与出射光之间的映射关系; 采用光学软件对系统的结构参数和非球面系数进行优化。计算平顶光束在出射距离20,30 mm时的输出能量均匀度。结果表明: 系统的工作焦深在20～30 mm时, 平顶区激光能量均匀度均大于78.0%。以锈蚀的低碳钢板为作用目标进行了激光清洗实验, 光斑作用区域内, 激光与物质相互作用均匀, 证明本设计能满足大功率激光使用环境的要求。

To reduce the edge effect of low energy outside the waist radius of a Gaussian beam when high-power laser equipment is operating and avoid the problems of edge and lap marks, it is necessary to design effective beam shaping. First, to reduce the complexity of the system and improve the utilization of the laser energy, a high-power Gaussian laser light source(average optical power of 500 W, pulse widths in 130-160 ns, wavelength of 1 064 nm, and power regulation range of 10%-100%) was optimized using the Galileo aspheric lens shaping system.Second, through the law of conservation of energy, the mapping relationship between incident and emitted light was obtained, and the structural parameters and aspheric coefficients of the system were optimized and simulated using optical software. The output energy uniformity of the flat-top beam at ejection distances of 20,25, and 30 mm was calculated. The results show that the energy uniformity of the flat-top region is greater than 78.0% when the focal depth of the system is between 20 and 30 mm. A laser cleaning experiment is conducted using a rusted low-carbon steel plate. The interaction between laser and material is uniform in the area of spot action, proving that the design can meet the requirements of high-power laser environments.