激光打孔用声光调Q阶跃脉冲Nd:YAG激光器

Pulse NdrYAG Laser for Drilling Modulated by Acousto-optic Q-switch

针对高质量激光打孔的应用要求,设计了一种高峰值功率脉冲激光器。采用声光器件对脉冲Nd:YAG激光进行了腔内调制,提高了激光脉冲的峰值功率。给出了激光器的结构、脉冲调Q的时序。获得了脉宽200ns的激光脉冲列,脉冲列的重复频率为(5～50)kHz,脉冲能量为30～80mJ,脉冲峰值功率为400kW,输出激光束的光束质量为3mm·mrad,并对飞机发动机燃烧室用1.5mm厚镍基高温合金进行打孔实验,获得了再铸层薄和微裂纹少的微孔。

According to the application requirement of high-quality drilling, the authors design a novel high peak-power acousto-optical Q-switched pulse Nd:YAG laser. AOM is used in cavity to modulate pulse Nd:YAG laser for improving peak-power of laser pulse. The set-up and Q-switching pulse sequence of laser are given. The Q-switch pulse train of laser with the duration of 200 ns during each flash-lamp pulse is obtained. The repetition rate of the train is (5-50)kHz, the pulse energy is 30~ 80 mJ, and the peak power is more than 400 kW with an output beam parameter product of about 3 mm mrad. The laser has been used to drill the Ni-alloy of 1.5 mm thick, resulting in thinner recast layer and less micro cracks.