【作者】 肖凯博； 蒋新颖； 袁晓东； 严雄伟； 李敏； 王振国； 李明中； 郑建刚； 郑万国；

【Author】 Kaibo Xiao;Xinying Jiang;Xiaodong Yuan;Xiongwei Yan;Min Li;Zhenguo Wang;Mingzhong Li;Jiangang Zheng;Wanguo Zheng;Research Center of Laser Fusion,China Academy of Engineering Physics;Collaborative Innovation Center of IFSA,Shanghai Jiao Tong University;Graduate School of China Academy of Engineering Physics;

【机构】 中国工程物理研究院激光聚变研究中心； 上海交通大学IFSA协同创新中心； 中国工程物理研究院研究生部；

【摘要】 针对重复频率运行下低温氦气冷却的间隔掺杂Yb:YAG叠片激光放大器中热效应的问题,提出了一种多层Cr⁴⁺:YAG热管理技术。利用三维有限元和琼斯矩阵方法,分析了不同Cr:YAG结构激光介质中温度和应力应变分布,并模拟计算了热致双折射退偏损耗和波前畸变。数值结果表明,通过设计两层和三层Cr:YAG结构,增益区内的横向温差降低到1.5 K以内,光束经过整个放大器后平均退偏损耗和波前畸变可分别减少到0.5%、0.8λ;进一步合理地设计Cr:YAG层数和吸收系数能有效消除热效应对光束质量的影响。更多还原

【Abstract】 In this paper, thethermal management techniqueof multi-layer Cr⁴⁺:YAG medium is presented for mitigatingthermal effects in cryogenichelium gas cooled Yb:YAG multislab amplifiers with Cr:YAG interlayers operating at a repetition rate.The distributions of temperature, stress,depolarization lossesandoptical path differencein four amplifier architectures with different Cr:YAGwere numerically calculated by a three-dimensional finite element analysis and the Jonesmatrices method.Numerical simulations show that the properly designed two-layer and three-layer Cr:YAGresult in a very small transverse temperature gradient（<1.5 K） in the first slab.The resulting averagedepolarization losses and optical path differencefor a laser headare reduced to 0.5% and 0.8 λ, respectively.Furthermore, the impact of thermal effects on the output beam quality can be vanish by properly designing the number, widths, and absorption of the multi-layer Cr:YAG.更多还原