摘要
为了说明高重复频率脉冲激光材料烧蚀时准真空环境效应的存在,对比不同重复频率的激光脉冲对钢材料的烧蚀率与不同气压环境中的烧蚀率,提出准真空环境效应是平均烧蚀率随脉冲重复频率的提高显著增加的主要原因。将激光脉冲作用形成的准真空环境分为激光等离子体冲击波存在时的准真空环境和激光等离子体冲击波消散后的准真空环境两个时间段,模拟计算和分析了激光作用区周围环境气体密度分布及准真空环境持续时间。实验结果表明,在激光脉冲作用后的几百微秒内,激光烧蚀区周围会存在准真空环境,若后续脉冲在此时间范围内作用于材料,会产生类似于在真空环境中烧蚀的高烧蚀率。
Effect of quasi vacuum environment during pulsed laser ablation with high repetition rate is investigated. The comparison of ablation rates for pulsed laser drilling in steel with different repetition rates and different ambient pressures shows that the quasi-vacuum environment can be the main reason for the increase of ablation rate during high-repetition-rate pulsed laser ablation. The density distributions of ambient air are investigated in two different time scales. The experimental results show that the quasi-vacuum environment occurs in the pulse laser ablation and continues for several hundred microseconds after laser pulse. If the subsequent laser pulse interacts with the material during this time, the high ablation rate will be achieved as that obtained in vacuum.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2009年第1期238-243,共6页
Chinese Journal of Lasers
