基于混合算法的高均匀度超快激光分束及精密加工研究  

High⁃Uniformity Ultra⁃Fast Laser Beam Splitting and Precision Machining Based on Hybrid Algorithm

作　　者：杨磊 徐新宇 王建磊[3] 叶云霞[1,2] 任旭东[1] 陈卫标[3] Yang Lei;Xu Xinyu;Wang Jianlei;Ye Yunxia;Ren Xudong;Chen Weibiao(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China;Institute of Micro-nano Optoelectronics and Terahertz Technology,Jiangsu University,Zhenjiang 212013,Jiangsu,China;Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013 [2]江苏大学微纳光电子与太赫兹技术研究院,江苏镇江212013 [3]中国科学院上海光学精密机械研究所,上海201800

出　　处：《中国激光》2023年第16期287-297,共11页Chinese Journal of Lasers

基　　金：江苏省自然科学基金(BK20170559);江苏省博士后科学基金(2020Z016);镇江市重点研发计划(GY2019005);江苏省重点研发产业前瞻项目(BE2020037)。

摘　　要：基于空间光调制器外光路分束进行并行加工是提高超快激光加工效率的有效方法。高均匀度分束算法是实现外光路分束的关键。在实际光路中,由于光路不完全满足理论条件,经典的GS算法生成的多光束均匀度远低于理论值,不满足阵列化激光加工的要求。基于GS‑GA算法的思想与图像处理技术,在程序设计中引入了实时反馈的功能,以达到提高分束均匀度的目的。并采用加载菲涅耳透镜相位的方式分离零级光,避免重建光场离轴带来的畸变。最终实现了均匀度接近94%的分束,并通过加工实验验证了高均匀度分束算法在精密加工中的应用效果。Objective Ultrafast lasers possess desirable advantages in the field of precision processing owing to their short pulse widths and high-energy peak densities.However,single-focus ultrafast laser processing technology suffers from low processing efficiencies.Parallel processing by beam splitting using a spatial light modulator(SLM)is a solution for improving the efficiency of ultrafast laser precision processing.Improving the multibeam uniformity after beam splitting is a key issue in ultrafast laser parallel processing.Two factors deteriorate the quality of multiple beams:the approximations in beam-splitting algorithms,which leads to poor calculation accuracy,and the poor beam quality of the laser in optical paths.To address these issues,a feedback GS-GA algorithm based on real-time feedback is proposed in this study.Methods A spatial light modulator is used for phase-only modulation by loading computer-generated holograms(CGHs).The algorithms for beam splitting and shaping are dominated by the Gerchberg-Saxton(GS)algorithm and its derivatives.The GS algorithm is highly sensitive to the initial phase value of the light source,which directly affects the quality of the reconstructed light field.However,it is difficult to obtain a suitable initial value.In this study,real-time feedback based on GS and genetic algorithms is introduced in the process of hologram generation to improve the uniformity of beam splitting.In addition,a loaded Fresnel lens phase is used to separate the zero-order beam,avoiding the aberration caused by deviations from the optical axis of a reconstructed optical field.After several iterations of the proposed algorithm,a beam array with a high uniformity is designed.Results and Discussions Three beam splitting methods,including the GS algorithm,GS-GA algorithm,and feedback GS-GA algorithm,are investigated in terms of the beam splitting and processing effect.Owing to a system error in the optical path,the multibeam uniformity derived from the GS algorithm is less than 80%of the theoretical value

关 键 词：激光技术 空间光调制 分束整形 超快激光精密加工 遗传算法 GS算法 

分 类 号：TN249[电子电信—物理电子学]