Surface profile of material ablated with high-power lasers in ambient air medium
Surface profile of material ablated with high-power lasers in ambient air medium
复制标题
在环境空气介质中用高功率激光烧蚀的材料的表面轮廓
DOI：
10.1063/1.1846141
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发表时间：
2005
影响因子：
3.2
通讯作者：
S. Nikumb
中科院分区：
文献类型：
--
作者：
S. R. Vatsya;Chengde Li;S. Nikumb
一般来说，只要激光光束的强度轮廓成形良好，用高功率超短脉冲激光进行材料加工就能产生更干净的表面。然而，光束在通过环境大气介质(如空气)传输时会出现失真。穿过这样的介质会导致光束自聚焦，进一步增加强度，导致气体击穿。产生的等离子体扭曲了光束的原始轮廓，烧蚀表面符合光束轮廓。本文提出了一种计算光束通过介质的光强分布的数值方法。然后根据光束的光强分布，通过最近发展起来的几何方法来确定被加工表面的轮廓。将计算得到的轮廓与实验得到的表面进行了比较，两者吻合较好。对于中等大小的光斑，自聚焦效应和等离子体效应往往相互抵消，使光束的强度分布保持与其他光斑相似的光强分布。
In general, material processing with high-power ultra-short-pulsed lasers yields cleaner surfaces, as long as the intensity profile of the laser beam is well shaped. However, the beam suffers distortions during propagation through ambient atmospheric media such as air. Passage through such media causes the beam to self-focus, increasing the intensity further and causing the breakdown of the gas. The resulting plasma distorts the beam’s original profile and the ablated surface conforms to the beam profile. A numerical scheme is developed here to calculate the intensity profile of an optical beam propagating through a medium. Intensity distribution of the beam is then used to determine the profile of the processed surface by a geometrical method developed recently. The calculated profile is compared with the experimentally obtained surface with good agreement. For medium spot sizes, the self-focusing and plasma effects tend to cancel each other, maintaining the intensity profile of the beam similar to the o...