在全面分析碱金属蒸气激光放大器的激光动力学与流体动力学过程的基础上,结合热效应、饱和放大效应、放大自发辐射、高能级激发与电离的影响,建立了一个相对完善的物理模型来模拟流动散热条件下半导体抽运碱金属蒸气激光放大器的输出特性。计算模拟了纵向和横向两种不同流动方式下,气体流速对输出功率的影响,比较分析了高抽运功率密度下各能级粒子数密度的变化趋势,最后模拟了各级放大器的功率分配比对提高级联放大器输出效率的作用。结果表明:在相同工作温度条件下,多个等长蒸气池和均等抽运光功率分配能让高级数放大器获得比低级数放大器更高的放大倍数。所提模型有助于高功率碱金属蒸气激光放大器的参量选择和优化设计。

Based on the comprehensive analysis of laser kinetics and hydrodynamic processes of alkali vapor laser amplifiers and combined with the thermal effect, saturation amplification effect, amplified spontaneous emission, and high level excitation and ionization, a comparatively ideal physical model is established to simulate the output characteristics of diode-pumped alkali vapor laser amplifiers under flow and heat dissipation conditions. The influence of gas flow velocity on output power is simulated with two different flow modes in longitudinal and transverse directions. The variation trend of the particle number density at high pumping power density is compared and analyzed. Finally, the effect of the power distribution ratio of the amplifier in each stage on the improvement of cascade amplifier output power is simulated. Results show that under the same operating temperature condition, multiple equal-length steam pools and equal distribution of pumping power allow high-level amplifiers to achieve higher magnification than that of low-level amplifiers. Thus, the model contributes to the parametric selection and optimization of the design of alkali vapor laser amplifiers.