为了构建一种声光调Q的窄脉宽小型Nd∶YVO4激光器, 从主动调Q速率方程出发, 分析了抽运速率、重复频率、输出镜透过率对脉宽的影响。该激光器采用简单的平平腔设计, LD端面抽运高增益的Nd∶YVO4激光晶体, 在谐振腔内插入一个微型的声光调Q开关, 作用长度约为7mm, 谐振腔腔长13mm, 输出镜的透过率为70%。结果表明, 在抽运功率为4.21W、重复频率20kHz时,获得了单脉冲能量20μJ、脉冲宽度1.65ns、峰值功率为12kW的1064nm激光输出。此结果说明, 用微型声光调Q开关来构建短腔获得窄脉宽输出是一种切实可行的方案, 且该器件还可以作为大功率激光器的种子源。

In order to construct a micro acousto-optic Q-switched Nd∶YVO4 laser with narrow pulse width, based on active Q-switched rate equation, the influence of pump speed, repetition rate and output mirror transmittance on pulse width was analyzed.The laser was designed with the structure of simple flat-flat cavity. High gain Nd∶YVO4 laser crystal was end pumped by LD. A micro acousto-optic Q-switched was inserted in the resonant cavity,with action length of 7mm, cavity length of 13mm, and output mirror transmittance of 70%.The results show that when the pump power is 4.21W and repetition rate is 20kHz, the output of 1064nm laser was obtained with single pulse energy of 20μJ, pulse width of 1.65ns and peak power of 12kW. It is feasible to use micro acousto-optic Q-switched to construct short cavity and obtain narrow pulse width output. The device can also be used as the seed source of high-power lasers.