激光烧蚀金属靶诱导靶电势效应的机理研究

利用Nd∶YAG脉冲激光烧蚀Cu靶材,实验研究了不同激光能量下等离子体诱导靶上电势的演变规律.结果表明：靶上电势信号呈现显著的双峰结构,第一个峰出现在激光烧蚀开始之后约20 ns,持续时间仅约50 ns；而第二个峰出现约35 μs之后,持续时间达到了上百微秒.通过对实验结果的详细分析可知靶上电势信号的产生是激光等离子体荷电效应引起的,并提出了等离子体对金属靶的静电感应、电荷复合-转移效应机制,解释了靶上电势信号的演变规律.

Mechanism Study on Potential Signal in Laser-Induced Cu Target

A tiny Cu column was used to be the metal target to detect potential signals induced by Nd∶YAG laser in air.The signals show that a clear twin peak distribution in the temporal profile.The fist peak has a duration about 50 ns and delays 20 ns with respect to laser irradiation.The second peak appears about 35 μs later and has a duration about several hundred μs.The experimental results show that the signal intensity increases near linearly with the laser energy.The time dependent characteristics are analyzed at length,the laser plasma carrying charges is considered to why the potential signal appears on the metal target,and a kind of mechanism of electric-inducing and charge-transferring is put forward.