采用中心波长为940 nm的激光二极管泵浦，实现了Yb:YAG薄片的Cr4+:YAG被动调Q 激光输出.Yb:YAG薄片掺杂Yb3+离子浓度为10%，厚度为500 μm.理论上计算了Yb:YAG薄片在直接水冷方式与不同厚度SiC冷却方式下的温度分布.实验中采用厚度800 μm的SiC冷却方式，获得了最高功率2.8 W的1 030 nm连续激光输出，输出功率相比直接水冷方式提高了40%.通过Degnan理论优化了被动调Q晶体Cr4+:YAG的初始透过率和输出耦合镜，采用初始透过率为93%的Cr4+:YAG晶体和透过率为10%的输出耦合镜，在800 μm SiC冷却方式下，获得了平均输出功率1.95 W、单脉冲能量1.2 mJ、脉冲宽度74 ns、重复频率1.6 kHz的稳定调Q脉冲输出，斜效率为18.1%.光束质量因子M2x=1.622，M2y=1.616.

Using 940 nm diode laser as pumping source, a passively Q-switched Yb:YAG thin disk laser by Cr4+:YAG was realized. The Yb:YAG disk with 500 μm thickness was employed，the Yb3+ atom fraction is 10%.The distribution of temperature in Yb:YAG disk with direct water cooling and SiC cooling with different thickness was theoretically simulated, respectively. The maximum output power of 2.8 W at 1 030 nm was obtained with 800 μm SiC cooling, the output power has increased by 40% than that obtained with direct water cooling. The initial transmission of Cr4+:YAG crystal and the output coupling rate were optimized by Degnan′s theory. With the initial transmission of Cr4+:YAG crystal of 93% and the output coupling rate of 10%, a stable pulse train of 1.95 W averaged output power with a pulse energy of 1.2 mJ and pulse width of 74 ns were obtained with 800 μm SiC cooling. The repetition rate is 1.6 kHz, the slope efficiency is 18.1%, and the beam quality M2x=1.622, M2y=1.616.