气体冷却激光二极管抽运的固体激光放大模块设计及热管理研究

Gas-Cooled Laser Diode-Pumped Solid-State Laser Amplification Module Design and Thermal Management

激光二极管抽运的固体激光器(DPSSL)成为实现下一代激光器驱动装置对能量转换效率和重复频率要求的重要途径。高重复频率导致介质内存在热积累,引起热光效应、弹光效应和形变,导致波前畸变的产生,影响光束质量。针对目标输出能量100J,重复频率10Hz的放大模块,分析其储能提取效率和增益性能,采用气体冷却技术,设计激光二极管抽运的片状放大模块结构。利用有限元数值分析方法,建立了该装置单片放大器热分析模型,研究了单片增益介质厚度、对流换热系数对波前畸变的影响,结合波前畸变的要求,得到了单片厚度的最优值,并对该设计进行热分析,利用超高斯光束近似抽运光源,结合氦气气流分布情况,模拟单片介质的温度、形变和应力分布,计算得到了热光效应、形变和弹光效应对波前畸变的贡献以及单片增益介质的总波前。

Laser diode pumped solid-state lasers（DPSSL）has become an important way to realize the next generation of laser-driven device for energy conversion efficiency and repetition rate requirements.High repetition frequency leads to heat accumulation on the memory medium,which will cause thermo-optical effect,elasto-optical effect and bulk displacement,then resuls in the generation of wavefront distortion and affects the beam quality.Aimed at 100 J output energy and 10 Hz repetition frequency amplifier module,the extraction efficiency and gain performance storage are analyzed,and the sheet laser diode pumped amplifier module structure is designed using gas cooling technology.Thermal analysis models of single slice amplifier are established using the finite element analysis.The influence of signal slice thickness and convective heat transfer coefficient to the wavefront distortion are researched,in consideration of the limitation of the total wavefront distortion,we obtain the optimal value of single slice thickness.Using super-Gaussian beam on behalf of pump source and considering the distribution of helium gas flow,we analysis the thermal designed data and simulate the temperature,bulk displacement and stress distribution to get the related wavefront distortions.