直接液冷薄片激光器波前畸变优化研究  

Optimization of Wavefront Distortion of Direct Liquid-Cooled Thin-Disk Laser

作　　者：魏前明 阮旭[2,3] 易家玉[2,3] 马宇 Wei Qianming;Ruan Xu;Yi Jiayu;Ma Yu(Sino-French Institute of Nuclear Engineering and Technology,Sun Yat Sen University,Zhuhai 519000,Guangdong,China;Institute of Applied Electronics,Chinese Academy of Engineering Physics,Mianyang 612000,Sichuan,China;Key Laboratory of High Energy Laser,Chinese Academy of Engineering Physics,Mianyang 612000,Sichuan,China)

机构地区：[1]中山大学中法核工程与技术学院,广东珠海519000 [2]中国工程物理研究院应用电子学研究所,四川绵阳612000 [3]中国工程物理研究院高能激光重点实验室,四川绵阳612000

出　　处：《中国激光》2022年第23期26-32,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(U1830118)。

摘　　要：对于直接液冷薄片激光器而言,实现功率的定标放大可以在保证泵浦光强恒定的情况下通过增大泵浦光斑的尺寸同时增加增益介质的尺寸或数量来实现。这种设计理念自提出以来就得到了学术界的青睐。本团队针对高功率直接液冷薄片激光器的实际工作条件,建立了单薄片双通道增益模块在对称情况下的模型,研究了微通道高度、薄片厚度、冷却液雷诺数等参数对激光器输出波前畸变的影响。结果表明:当其他条件一定时,随着微通道高度及薄片厚度的减小,激光器输出光束质量提高;随着冷却液雷诺数增大,激光器输出光束质量提高。经遗传算法优化后的设计参数产生的输出光束光程差均方根值为3.27μm,峰谷值为6.11μm,相较于经典文献设计参数下的均方根值和峰谷值分别降低了12.3%和15.6%。Objective With recent developments,the power of lasers has continuously improved,which has caused the inevitable increase in demand for laser output modules and heat dissipation,increasing the burden in terms of volume and weight as well as the serious problems of laser thermal effect on laser beam quality.Compared with traditional lasers,direct liquidcooled solid-state lasers use a gain medium to directly contact the cooling fluid for efficient heat exchange,which greatly reduces the laser’s cooling system weight.Scaling and amplification of the output power can be achieved by stacking the s lices in the gain module,and researchers favor its excellent characteristics.Therefore,a comprehensive optimization of the design of direct liquid-cooled solid-state lasers is required to discharge as much waste heat as possible and improve the output beam quality.Methods For the direct liquid-cooled thin-disk selected in this study,the gain module was composed of multiple thin-disk a rrays,and the pumping mode of double-side pumping was used.The pump beam enters the pump sheet array along the side of the gain sheet.The distance between them was approximately 0.3 mm,forming a typical microchannel structure,in which the specially treated laser cooling fluid flows at a high speed and removes waste heat in the thin disk.The laser was incident on the gain medium along the Brewster angle to reduce interface loss.The gain medium material was Nd∶YAG crystal,and the cooling fluid was heavy water.As the working conditions of each gain sheet were the same,the optical path difference generated by the gain medium and half-flow field of the microchannel on both sides was selected as the research object.The temperature of the sheet was calculated by Fourier’s law,the flow field of the microchannel was c alculated using the Navier-Stokes equation,the SST(Shear Stress Transport)model was selected as the solution model,and the stress and deformation field of the gain medium were calculated using related technology.Finally,the obtained

关 键 词：激光器 直接液冷 薄片激光器 耦合模拟 波前畸变 遗传算法优化 

分 类 号：TN248.1[电子电信—物理电子学]