中文摘要：

报道了2μm被动调Q的Ho∶YAG激光器,该激光器采用Tm^（3＋）光纤激光器作为泵浦源,使用多层石墨烯作为可饱和吸收体。在连续波激光输出模式下,当泵浦功率为4.2 W时,获得了750 mW激光输出,输出激光中心波长为2.09μm,斜率效率为29.6%。在连续波激光器谐振腔中插入多层石墨烯可饱和吸收体并调整谐振腔,获得了脉冲激光输出。当泵浦功率为4.2 W时,获得最小脉冲宽度3.1μs、重复频率66.6 kHz的脉冲激光输出,其最大平均输出功率为170 mW,斜率效率为12.6%,光束质量因子M_x^2=1.15,M_y^2=1.12。

英文摘要：

A 2 μm passively Q-switched（ PQS） Ho∶ YAG laser pumped by a Tm~（3＋） fiber laser was demonstrated with a multilayer graphene as the saturable absorber. In the continuous wave（ CW）mode,a 2. 09 μm laser with the output power of 750 m W was obtained at the incident pump power of 4. 2 W,corresponding to the slope efficiency of 29. 6%. By inserting a multilayer graphene as the saturable absorber and adjusting the cavity,we achieved passively Q-switched laser pulses. The minimum pulse duration was obtained at the pump power of 4. 2 W with the repetition rate of 66. 6kHz and the pulse width of 3. 1 μs. The maximum output power of 170 mW was achieved,corresponding to the slope efficiency of 12. 6%. The beam quality factors are M_x~2= 1. 15 and M~y_2= 1. 12,respectively.