研究了输出波长为2.018 μm的激光二极管(LD)抽运Tm:YAG激光器。通过准三能级系统的速率方程, 分析了激光系统的抽运阈值和斜率效率。同时, 利用ABCD矩阵分析了平凹腔和双凹腔的腔型稳定条件和模式匹配情况。实验时采用785 nm的光纤耦合半导体激光器为抽运源, 当采用平凹直腔, Tm:YAG晶体为5 ℃时, 获得了4.04 W的连续激光输出, 激光器斜率效率为35.4%, 光-光转换效率为26.4%。实验比较了不同晶体温度下Tm:YAG激光器的阈值、功率和效率。实验结果与理论分析基本吻合。此外, 还研究了激光器腔型对激光输出功率和效率的影响。

Laser diode (LD) end pumped Tm:YAG laser was experimentally investigated. The threshold pump power and slope efficiency were discussed by using the quasi-three-level rate equations. The stability conditions of Tm:YAG laser resonators and mode matching between the pump beam and the cavity mode were analyzed by using the ABCD matrix. In the experiments a 785 nm fiber-coupled LD was used to pump the Tm:YAG laser. 4.04 W continuous output power was obtained at 2.018 μm with the laser crystal temperature of 5 ℃ in a plane-concave cavity. The slope efficiency of the Tm:YAG laser was 35.4% and the total optical-optical conversion efficiency was 26.4%. The threshold, output power and slope efficiency of Tm:YAG laser at different crystal temperatures were investigated. The experimental results agree with the theoretical estimation. The influences of the laser resonator on the laser output power and efficiency were also discussed.