中国物理B ›› 2020, Vol. 29 ›› Issue (5): 54209-054209.doi: 10.1088/1674-1056/ab8206
• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇 下一篇
Chao Tan(谭超), Lin-Jie Zhao(赵林杰), Ming-Jun Chen(陈明君), Jian Cheng(程健), Zhao-Yang Yin(尹朝阳), Qi Liu(刘启), Hao Yang(杨浩), Wei Liao(廖威)
Chao Tan(谭超)1, Lin-Jie Zhao(赵林杰)1, Ming-Jun Chen(陈明君)1, Jian Cheng(程健)1, Zhao-Yang Yin(尹朝阳)1, Qi Liu(刘启)1, Hao Yang(杨浩)1, Wei Liao(廖威)2
摘要: CO2 laser rapid ablation mitigation (RAM) of fused silica has been used in high-power laser systems owing to its advantages of high efficiency, and ease of implementing batch and automated repairing. In order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics, an finite element method (FEM) mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations, to explore the 3D near-field light intensity distribution inside optics with repaired site on its surface. The influences of the cone angle and the size of the repaired site on incident laser modulation are studied as well. The results have shown that for the repaired site with a cone angle of 73.3°, the light intensity distribution has obvious three-dimensional characteristics. The relative light intensity on z-section has a circularly distribution, and the radius of the annular intensification zone increases with the decrease of z. While the distribution of maximum relative light intensity on y-section is parabolical with the increase of y. As the cone angle of the repaired site decreases, the effect of the repaired surface on light modulation becomes stronger, leading to a weak resistance to laser damage. Moreover, the large size repaired site would also reduce the laser damage threshold. Therefore, a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface damage. This work will provide theoretical guidance for the design of repaired surface topography, as well as the improvement of RAM process.
中图分类号: (Beam characteristics: profile, intensity, and power; spatial pattern formation)