热容运转模式下LD泵浦固体激光器的热效应分析

Analysis of thermal effect of solid state lasers in heat capacity mode

针对热容运转模式下的固体激光器,修正了二极管泵浦光强分布,并且考虑激光工作物质的比热容和热传导率随温度变化的特性,建立了三角均布脉冲LD侧面泵浦固体激光工作物质的热传导物理模型。利用有限元方法,模拟分析了激光工作物质的温度变化过程。结果表明,由于泵浦光的不均匀分布,热容运转模式下的固体激光器仍然会受到热效应的影响。分析比较了热容固体激光器和连续泵浦、脉冲泵浦模式下热稳态固体激光器工作物质的热效应,3种工作模式下,激光工作物质内的最大温差分别为3.59、35.51、8.07 K。表明热容运转模式下,激光工作物质内温度梯度非常小。讨论结果对热容激光器的设计工作提供了参考。

A heat transmission model for YAG crystal of a side-pumping solid state laser with triangle uniform distribution was established based on heat capacity mode and considering the diode pumped light intensity distribution, specific heat capacity,thermal conductivity and the properties of YAG materials varied with temperature. The finite element method was used to simulate and analyze the temperature change of laser crystal media,analysed results indicate that YAG operated in heat capacity mode can be affected by thermal effect from asymmetric pumping light. The thermal effects of different YAGs including heat capacity model, continuous pumping and pulse pumping model were compared and analyzed, compared results show that the maximal temperature differences of the three models are 3.59,35.51 and 8.07 K, respectively,which suggests that the smallest temperature difference is at the heat capacity mode and the results can provide a reference for the design of heat capacity laser.