椭圆高斯分布半导体激光器泵浦被动调Q激光器的优化

在考虑泵浦光束和初始反转粒子数椭圆高斯分布的条件下,确定了新的调Q耦合速率方程。在椭圆高斯分布近似下,通过数值分析的方法针对脉冲能量进行优化,首次得到了归一化的脉冲能量和反射镜反射率等关键参数与无量纲变量z的关系曲线。文中以半导体激光器贴近端面泵浦,Cr4+:YAG作为饱和吸收体的Nd:YVO4被动调Q激光器为例进行了脉冲能量优化计算,在小信号透过率为75%,反射率91.8%时,对应最大脉冲能量1.5 J,峰值功率81 W,脉冲宽度18.4 ns。选用小信号透过率为73.4%的饱和吸收体和反射率为87%的反射镜进行实验验证,得到的脉冲能量为1.25 J,峰值功率为76.4 W,脉冲宽度为16.3 ns。理论计算与实验结果基本相符。

Optimization of passively Q-switched lasers pumped by ellipse Gaussian distribution LD

New coupler Q switch rate equations were obtained by taking account that the intracavity photo density and the initial population-inversion density are both ellipse Gaussian distributed. The space dependent rate equations were solved numerically. The key parameters like maximum energy, optimized reflectivity, and optimized small signal transparency were determined under the ellipse Gaussian distribution approximation, and a group of general curves were generated for the first time. The optimal calculations for a diode laser near end pumped passively Nd:YVO4 laser was presented to demonstrate the use of the curves and related formulas, the maximal pulse energy of 1.5 J, peak power 81 W, and pulse width 18.4 ns can be obtained when small signal transparency T0 is 75% and reflectivity 91.8% after calculation. The pulse energy of 1.25 J, peak power 76.4 W and pulse width 16.3 ns was obtained by using a saturable absorber with 73.4% small signal transparency and a 87% reflector in experiments. Experiments agree with theoretical results well.