组合式钕玻璃片状激光放大器增益性能的动态模拟

THE DYNAMIC MODULATION FOR GAIN PERFORMANCE IN MULTI-SEGMENT Nd:GLASS DISK LASER AMPLIFIERS

用随时间变化的氙灯辐射光谱模型 ,建立了组合式钕玻璃片状激光放大器动态增益特性的模拟程序 ,实现了从氙灯放电到引出激光的全过程动态模拟 ,可用于片状激光放大器的优化设计 .研究了 :1)放大器在不同的抽运条件下水平方向的增益均匀性 ,当氙灯爆炸系数比较高时 ,自发辐射放大优先使片的边缘产生消抽运作用 ,增益分布变得不均匀 ,通光口径的中央处增益较大 ;2 )片厚度和掺杂浓度对增益性能的影响 ,在相同的抽运条件下 ,储能通量由片厚度与掺杂浓度的乘积决定 。

Based upon the instantaneous output spectra of a xenon flashlamp, we have constructed a unique dynamic modeling program to predict the gain performance of multi-segment Nd : glass laser amplifiers. The model, which includes all the dynamic modulations from flashlamp discharging to laser output, may be used in the laser amplifier system optimization. The gain uniformity in the horizontal direction is investigated with the modeling program. The amplified spontaneous emission inside a laser slab first increases the overall decay rate and thereby decreases the stored energy at the slab edges. The stored energy density at the slab center is higher than that at the slab edges when the explosion fraction of the flashlamp becomes large. The influences of the disk thickness and Nd2O3 doping level on gain performance are also studied with the modeling program. The stored fluence is determined by the doping - thickness products ( Nd ion concentration x slab thickness) in the multi-segment amplifiers slab, and the details are also given.