A comparison of single and double pulse laser-induced breakdown spectroscopy of aluminum samples
A comparison of single and double pulse laser-induced breakdown spectroscopy of aluminum samples
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DOI：
10.1016/s0584-8547(02)00058-7
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发表时间：
2002-07
期刊：
影响因子：
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通讯作者：
F. Colao;V. Lazic;R. Fantoni;S. Pershin
中科院分区：
文献类型：
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作者：
F. Colao;V. Lazic;R. Fantoni;S. Pershin
对空气中的铝样品进行了单脉冲和双脉冲激光诱导击穿光谱(LIBS)研究。在双脉冲激发的情况下，使用工作在相同波长(大多数情况下为1064 nm)的相同激光光源进行了实验。在所研究的两个脉冲(40-60μS)之间的时间延迟内，观察到了第二脉冲等离子体阈值的降低和线发射的整体增强。在点火阈值附近研究了单脉冲和双脉冲产生的激光诱导等离子体，以研究在不同区域内可能的动力学机制。目前已有的等离子体光谱诊断方法，如谱线展宽和斯塔克效应引起的漂移，已经被用于表征以恢复电子密度，而标准的温度测量是基于玻尔兹曼曲线。在长时间尺度上测量了等离子体衰变过程中的等离子体相关参数，如温度和电子密度，并与陨石坑的形状(直径和推算体积)进行了比较。在保持单脉冲能量不变的情况下，对双脉冲和单脉冲激光激发进行了比较，并考察了激光能量的影响。结果表明，在常规实验室实验中，使用双脉冲技术可以显著提高LIBS技术的分析能力。
Single and double pulse laser-induced breakdown spectroscopy (LIBS) was carried out on aluminum samples in air. In the case of double pulse excitation, experiments were conducted by using the same laser source operated at the same wavelength (1064 nm in most cases here presented). A lowering of the second pulse plasma threshold was observed, together with an overall enhancement in line emission for the investigated time delay between the two pulses (40–60 μs). The laser-induced plasma originated by a single and double pulse was investigated near ignition threshold with the aim to study possible dynamical mechanisms in different regimes. Currently available spectroscopic diagnostics of plasma, such as the line broadening and shift due Stark effects, have been used in the characterization in order to retrieve electron densities, while standard temperature measurements were based on Boltzmann plot. Plasma relevant parameters, such as temperature and electron density, have been measured in the plasma decay on a long time scale, and compared with crater shape (diameter and inferred volume). The comparison of double with single pulse laser excitation was carried out while keeping constant the energy per pulse; the influence of laser energy was investigated as well. Results here obtained suggest that use of the double pulse technique could significantly improve the analytical capabilities of LIBS technique in routine laboratory experiments.