大功率扩散冷却型Slab CO_2激光器光束质量的研究

Study on the beam quality of high power Slab CO_2 laser

本文对国际上最新的大功率扩散冷却型SlabCO_2激光器的光束质量进行了全面的测量与实验研究。从原始激光束的光束质量、通过导光系统后激光束质量、聚焦光斑的质量以及焦点漂移四个方面全面考察了SlabCO_2激光器的光束质量以及光束的传输、聚焦特性。结果表明,SlabCO_2激光器具有高光束质量,其M2因子非常接近1的理想值;激光束具有良好的传输和聚焦性能,可以长距离传输;使用焦距为300mm的聚焦镜聚焦,聚焦光斑的束腰半径约为134μm,光束横截面能量分布接近理想的高斯分布,焦深约为5mm,在加工范围内(3m),激光束的焦点漂移量大约为1mm。另外,采用SlabCO_2激光器对厚度为10mm的低碳钢在不同的离焦位置进行激光深熔焊接实验,讨论了激光光束质量和焦深对焊接结果的影响。

In this paper, the beam quality and beam characters of propagation & focus of the high-power diffusion-cooled Slab CO_2 laser are studied both in measurement and experiment. The beam quality is measured in four aspects: before and after the beam through the flying optics, focal beam and focal shift. The measurement results show that the Slab CO_2 laser beam with high beam quality. It's M2 factor is approaching the ideal value 1 and the beam intensity profile remains Gauss Profile. Laser beam with good propagation and focus characters. The beam can propagate a long way and can be focused with lens with long focal distance. The focal beam waist radius is 134μm, the focal distanced of the focus lens is 300mm. It's focal depth is about 5mm and the focal shift is about 1mm in the range of processing (3m). In addition, the experiments of laser welding mild carbon steel with thickness of 10mm are operated under different defocused position and ideal welding quality are got. Finally, the problems of laser beam quality and focal length effect on the welding quality are discussed.