热容激光器在激射过程中,激光介质的温度快速升高,导致了热容激光器具有特殊的激光输出特性。通过理论分析、数值模拟和实验研究等方法,对热容激光器的激光输出特性进行研究,掌握热容激光器工作的基本规律,为热容激光器的设计、实验提供了重要的参考。建立了描述热容激光输出特性的理论模型,给出了输出功率随激光介质温升及工作时间的变化关系。数值模拟研究结果表明,激光介质的温度从300 K升高到400 K过程中,阈值功率密度从2.6 W/cm3增加到33.6 W/cm3,输出功率下降7%。利用建立的热容激光器实验装置,测量了不同占空比情况下的输出功率,占空比越高输出功率随时间下降得越快,与数值模拟结果相符。在低占空比时,数值模拟和测量结果吻合较好;在高占空比时出现误差,而且占空比越高误差越大。

When the heat capacity laser is operating, the temperature of the laser medium is rising, so heat capacity laser has special laser output characteristics. For mastering the basic working rule of heat capacity laser, the output characteristics in course of lasering were studied by theoretical analysis, numerical simulation and experiment research, which will provide references for the experimental study and design of heat capacity laser. The theoretical model of heat capacity laser output characteristic was established. The relation of the output power to the temperature and time was got. The results of numerical simulation show that when the temperature of the laser medium increased from 300 K to 400 K, the threshold power density increased from 2.6 W/cm3 to 33.6 W/cm3 and the output power reduced by 7%. The output powers at different repetition rate were measured and compared with calculation. The higher duty cycle was, the fast the output power reduced. The simulating results accorded well with experimental data at low duty cycle, but there is relative big error at higher duty cycle.