固体激光器晶体吸收光场的设计仿真

设计了3类8种二极管侧面泵浦结构，构建了相应的泵浦光学理论模型，采用有限元分析方法，计算了不同结构下的吸收效率和矩阵元素标准差。首先，在给定泵浦总功率、芯片间距、掺杂浓度等前提下，随着泵浦距离在0～5 mm内递增，8种泵浦结构中激光晶体的吸收效率呈降低趋势，矩阵元素标准差也逐渐减小，其中部分结构在近距离(0～0.3 mm)泵浦时矩阵元素标准差变化程度较大，在实际应用中应避免泵浦距离处于近距离区间。其次，在相同结构参量下，随着晶体掺杂浓度在0.6%～1.0%内增加，激光晶体的吸收效率提高，同时，掺杂浓度提升也是造成截面中心峰值降低或半径方向上光场凹陷的原因。因此，掺杂浓度和泵浦距离的匹配将是提升半径方向上均匀性分布的有效手段。

Design and Simulation of Crystal Absorption Light Field in Solid-state Laser

In this paper, three types of eight kinds of diode side-pumped structures were designed, and the corresponding theoretical model of pumping optics was constructed. The absorption efficiency and standard deviation of matrix elements under different structures were calculated by finite element analysis method. First, given the total pump power, chip spacing, doping concentration, etc., with the increase of the pump distance from 0~5mm, the absorption efficiency of laser crystal in the eight pump structures tended to decrease, and the standard deviation of matrix elements also decreased gradually. The standard deviation of matrix elements varied greatly when some structures were pumped at a close distance (0~0.3mm). In practical applications, the pump distance should be avoided in the above range. Secondly, under the same structural parameters, the absorption efficiency of the laser crystal was improved with the increase of the crystal doping concentration from 0.6% to 1.0%. At the same time, the increase of the doping concentration was the source of the reduced central peak of the cross section or light field depression in the radius direction. Therefore, the matching of doping concentration and pump distance will be an effective means to improve the uniformity distribution in the radius direction.