利用879 nm新型激光二极管(LD)抽运Nd:GdVO4晶体,在室温下实现了4F3/2→4I9/2准三能级激光谱线跃迁。对掺杂原子数分数0.2%,3 mm×3 mm×3.8 mm的晶棒,在抽运功率为33 W时,获得912 nm最大输出2.5 W,斜率效率11%,相应的对吸收抽运功率的斜率效率达38%;对掺杂原子数分数0.2%,3 mm×3 mm×5 mm的晶棒,在抽运功率为33 W时,获得912 nm最大输出功率3.0 W,斜率效率16%,相应的对吸收抽运功率的斜率效率达45%。在腔内插入声光(AO)Q开关,当重复频率为10 kHz时, 获得了脉冲宽度为22 ns,平均功率为660 mW,峰值功率达3 kW。理论上分析了晶体的长度、浓度与准三能级激光器振荡阈值的关系,讨论了再吸收损耗对激光器的运转状态产生的影响,并通过实验观察了再吸收损耗的饱和效应。

By use of novel 879 nm Laser Diode (LD), quasi-three-level transition in Nd:GdVO4 crystal at room temperature is realized. For the crystal with Nd doped concentration of 0.2% and 3 mm×3 mm×3.8 mm in size, wavelength of 912 nm. The 912 nm laser with output powe of 2.5 W when the pump power is 33 W, corresponding to a slope efficiency of 11% with respect to the pump power and a slope efficiency 38% with respect to the absorbed pump power. For the crystal with Nd doped concentration of 0.2% and 3 mm×3 mm×5 mm in size. The 912 nm laser with output power of 3.0 W is obtained when the pump power is 33 W, corresponding to a slope efficiency of 16% with respect to the pump power and a slope efficiency 45% with respect to the absorbed pump power. For the acousto-optic (A-O) Q-Switched regime, average output power of 660 mW and pulse duration of 22 ns is achieved at the repetition rate of 10 kHz, the peak power is up to 3 kW. The relationship between lasing threshold and the length and Nd doped concentration of crystal are theoretically analyzed. The influence of reabsorption loss on laser′s operation is discussed and the saturation effect of reabsorption loss is observed.