Investigation of plumes produced by material ablation with two time-delayed femtosecond laser pulses
Investigation of plumes produced by material ablation with two time-delayed femtosecond laser pulses
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DOI：
10.1016/j.apsusc.2009.04.061
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发表时间：
2009-09
影响因子：
6.7
通讯作者：
Sylvie Noël;E. Axente;J. Hermann
中科院分区：
文献类型：
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作者：
Sylvie Noël;E. Axente;J. Hermann
本文报道了在真空中用两束800 nm的飞秒激光脉冲对铜和金进行激光烧蚀的实验研究结果。通过快速羽流成像和时间和空间分辨光学发射光谱来监测烧蚀羽流动态。使用光学显微镜来跟踪作为两个激光脉冲之间的延迟的函数的烧蚀深度。用原子力显微镜分析了纳米粒子在云母衬底上的沉积。我们粗略估计羽流的雾化程度-这是雾化材料的质量分数超过总烧蚀质量-从原子和纳米粒子发射的辐射的相对强度。结果表明，原子化程度主要取决于两个激光脉冲之间的时间延迟和电子-晶格弛豫的特征时间。雾化程度的增加伴随着烧蚀深度的减小。原子力显微镜测量证实了部分雾化的纳米粒子，作为云母基板上的颗粒沉积的分析显示，两个脉冲之间的大延迟的纳米粒子的数量大幅减少。
We experimentally investigated and herewith reported the results of laser ablation of copper and gold with two time-delayed femtosecond laser pulses at 800nm in vacuum. The ablation plume dynamic was monitored by fast plume imaging and time- and space-resolved optical emission spectroscopy. Optical microscopy was used to follow the ablation depth as a function of the delay between the two laser pulses. Nanoparticles deposition on mica substrates was analysed by atomic force microscopy. We estimate roughly the plume's atomization degree – that is the mass fraction of atomized material over the total ablated mass – from the relative intensities of radiation emitted from atoms and nanoparticles. It is shown that the atomization degree depends critically on the time delay between both laser pulses and on the characteristic time of electron-lattice relaxation. The increase of the atomization degree is accompanied by the decrease of the ablation depth. Atomic force microscopy measurements confirm the partial atomization of nanoparticles, as the analyses of particle deposition on mica substrates show a large decrease of the number of nanoparticles for large delay between the two pulses.