强激光与粒子束, 2019, 31 (9): 091006, 网络出版: 2019-10-12
基于等离子体紫外辐射的强激光自动寻焦系统
A focus automatic positioning system of high-power laser beam based on plasma ultraviolet radiation
摘要
精准定位激光束焦点位置是提高激光雕刻、切割、焊接等加工精度的重要基础,而传统测量方法不适用于自动寻找强激光焦点。基于激光烧蚀金属后等离子发光含大量紫外谱线的原理,以日盲的氮化镓肖特基光电二极管为传感器,设计了以304不锈钢靶材为耗材的红外强激光束自动寻焦方法及其装置。该方法与共聚焦显微镜检测平均烧蚀坑深的方法相比,当以脉冲宽度100 ns、重复工作频率20 kHz、平均功率10 W的1064 nm光纤激光雕刻机为实验对象时,二者定焦位置相差24 μm。
Abstract
Accurate focus positioning of a laser beam is an important basis for improving laser engraving, cutting and welding accuracy, but the traditional methods are not fit for automatically finding high-power laser focuses. The plasma caused by laser ablating metal is able to emit a large amount of ultraviolet radiation. Therefore, in this paper a focus automatic positioning method for high-power infrared lasers is proposed and the relevant device is fabricated with a GaN Schottky photodiode as sensor and a 304 stainless-steel laser target as consumable material. As a contrast experiment, the depths of the laser ablation pits on the stainless-steel target are measured with a confocal microscope to find the deepest pits. The focal position difference is 24 μm between the two positioning methods, when the experiments using a 1064-nm-wavelength fiber laser engraving machine with a pulse width of 100 ns, a repetition frequency of 20 kHz and an average power of 10 W.
王馨梅, 郑泽彬, 范樱宝, 赖明玮, 魏锦禹, 吴新宇. 基于等离子体紫外辐射的强激光自动寻焦系统[J]. 强激光与粒子束, 2019, 31(9): 091006. Wang Xinmei, Zheng Zebin, Fan Yingbao, Lai Mingwei, Wei Jingyu, Wu Xinyu. A focus automatic positioning system of high-power laser beam based on plasma ultraviolet radiation[J]. High Power Laser and Particle Beams, 2019, 31(9): 091006.