Characterization of a collinear double pulse laser-induced plasma at several ambient gas pressures by spectrally- and time-resolved imaging
Characterization of a collinear double pulse laser-induced plasma at several ambient gas pressures by spectrally- and time-resolved imaging
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DOI：
10.1007/s00340-005-1758-9
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
G. Cristoforetti;S. Legnaioli;V. Palleschi;A. Salvetti;E. Tognoni
中科院分区：
文献类型：
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作者：
G. Cristoforetti;S. Legnaioli;V. Palleschi;A. Salvetti;E. Tognoni
通过光谱和时间分辨成像技术对共线双脉冲激光诱导等离子体进行了表征。两个 Q 开关 Nd:YAG 激光器的光束聚焦在真空室中的黄铜靶上以形成等离子体。使用增强型 CCD 以时间分辨率记录羽流发射强度和空间分布。使用一组干涉滤光片，我们收集了主要目标成分以及氧气的发射图像。实验过程中，激光脉冲间间隔（0 至 10 μs 范围内）和环境气压值（105 至 10 Pa 范围内）均发生变化。在大气压下，与同时脉冲相比，延迟激光脉冲观察到目标元件的线发射增强。然而，这种增强效果往往会在低压值下下降，并且在约 104Pa 的压力下观察到信号的减少。此外，据观察，增强因子的评估很大程度上取决于探测器的视场。还在几种压力和脉冲间延迟下研究了发射羽流的传播。
A collinear double pulse laser-induced plasma was characterised by means of a spectrally and time resolved imaging technique. The beams of two Q-switched Nd:YAG lasers were focused on a brass target in a vacuum chamber to form the plasma. The plume emission intensity and spatial distribution were recorded with temporal resolution using an intensified CCD. Using a set of interference filters, we collected images of the emission from the major target components as well as from oxygen. Both the laser inter-pulse separation (in the range between 0 and 10 μ s) and the ambient air pressure value (in the range between 105and 10 Pa) were varied during the experiment. At atmospheric pressure, an enhancement of the line emission from the target elements was observed for delayed laser pulses compared to coincident pulses. However, this enhancement effect tends to fall at low pressure values, and a decrease of the signal is observed for pressures under about 104Pa. Moreover, it was observed that the evaluation of the enhancement factor strongly depends on the detector field of view. The propagation of the emitting plume was also studied at several pressures and inter-pulse delays.