c切Nd∶YVO4/Cr4+∶YAG被动调Q 1 064 nm激光器实验研究

Abstract： Guided by the second-threshold theory， we constructed an LD end-pumped concave-plane resonator em • ploying 1%(at.) c-cut Nd∶YVO 4 as the gain medium and a Cr 4+ ∶YAG saturable absorber (initial transmission 95.09%)， and systematically optimized the output coupler transmittance (T OC )， cavity length (L cav )， the focal length ratio of the collimating and focusing lenses (f 1 ∶f 2 )， and the axial focus position.Experimental results indicate that the resonator' s gain-loss balance is governed primarily by T OC and L cav .Increasing L cav reduces the repetition rate and broadens the pulse， whereas shortening focal length of the focusing lens raises the repetition rate at the expense of a slight decrease in average power.The axial focus exhibits a single optimal position.With T OC =14.2%， L cav = 12 mm， f 1 ∶f 2 =10∶6.43， and fine focus adjustment， stable passively Q-switched operation at a pump power of 1. 9 W yielded an average output power of 501 mW， a repetition rate of 217 kHz， a pulse width of 14. 4 ns， and timing jit• ter≤700 ns.These results show that the second-threshold condition provides clear design and tuning guidelines for 文章编号： 1000-7032(2026)02-0330-10 收稿日期： 2025•12•03； 修订日期： 2025•12•10 基金项目： 吉林省科技发展计划项目(SKL202302027) Supported by Science and Technology Development Program of Jilin Province (SKL202302027) 第 2 期 胡千廷， 等： c 切 Nd∶YVO 4 /Cr 4+ ∶YAG 被动调 Q 1 064 nm 激光器实验研究 Nd∶YVO 4 /Cr 4+ ∶YAG passively Q-switched lasers.By matching output coupling， cavity geometry， and mode size and position to ensure rapid bleaching of the saturable absorber while enabling efficient energy extraction， one can achieve stable high-repetition-rate output with narrow pulse duration and low timing jitter.Owing to its smaller stimu• lated-emission cross-section and quasi-isotropic behavior in the c-cut configuration， Nd∶YVO 4 more readily satisfies the second threshold and supports high-repetition-rate operation， providing a sound basis for applications in precision machining， laser ranging， and nonlinear frequency conversion.Keywords： the second threshold condition； c-cut Nd∶YVO 4 ； passively Q-switched； high-repetition-rate