非稳腔大功率绿光激光器的研究

摘要

In order to improve its laser beam quality, obtain collimated laser beam and provide an excellent high-power green laser source to pump Ti:sapphire, a diode-side-pumped acoustic-optic Q-switched intra-cavity frequency doubling Nd:YAG laser was studied. In the experiment, a convex-plane unstable resonator was adopted assuming the convex mirrors and gain medium thermal lens as a telescope system. Experimental results show that a convex-plane unstable resonator has lager mode volume and better stability. Using a second type phase-matched KTP( KTiOPO4) for intra-cavity frequency doubling, with 200W pump power, 42W green laser was output with 109ns pulse width, 9. 3kHz pulse repetition frequency, less than 2mrad divergent angle, 21% optical-optical conversion efficiency and instability less than 2% during 24h work. It is proven that an effective output of green laser can be achieved with an unstable resonator and side pump module.%为了提高激光的光束质量和提供准直的平行光束,为抽运钛宝石提供优良的大功率的绿光抽运源,对激光二极管侧面抽运Nd∶YAG声光调Q腔内倍频固体激光器进行了研究.实验中采用凸平直线非稳腔,将凸面镜和增益介质热透镜效应等效为望远镜系统进行分析.由实验可知,凸平非稳腔具有较大模体积、良好的稳定性等优点;利用二类相位匹配的磷酸钛氧钾晶体进行腔内倍频,当抽运功率为200W时,获得脉宽109ns、重复频率9.3kHz、发散角小于2mrad 的42W绿光输出,光光转换效率达到21％,24h长时间的工作,不稳定性小于2％.结果表明,利用非稳腔腔型,在侧面抽运的模块中可以实现高效的大功率绿光输出.