为建立一个高效率的基模振荡器模型,采用谐振腔理论和ABCD定律计算分析了热透镜对腔内模式的影响,研究了不同泵浦源对斯托克斯因子的影响。研究结果表明,在热透镜焦距300~350mm范围内腔模变化较小,采用914nm泵浦源可以提高斯托克斯因子从而提高振荡器效率。设计的基模振荡器在泵浦功率为50 W时,可得到34.7 W的激光输出,效率达到69.4%。 In order to establish a high efficiency base oscillator model, the effects of thermal lens on cavity modes were analyzed by using resonator theory and ABCD law, and the influence of different pumping sources on Stokes’ factor was studied. The results show that in the thermal lens focal length 300 ~ 350mm cavity mode change is small, the use of 914nm pump source can improve the Stokes factor to improve the oscillator efficiency. The design of the fundamental oscillator gives a laser output of 34.7 W at a pump power of 50 W, with an efficiency of 69.4%.