双脉冲飞秒激光诱导Fe等离子体光谱

发布时间：2018-07-10 09:14

本文选题：双脉冲 + 飞秒激光　；参考：《吉林大学》2015年硕士论文

【摘要】：激光诱导击穿光谱（LIBS）技术作为一种分析工具，自问世以来，就被公认为是一种前景广阔的新技术。随着激光器、光谱仪等相关仪器的不断更新进步，超短脉冲激光器被引入到激光诱导等离子体光谱技术中来，使LIBS技术进入了飞秒时代；由于脉冲激光系统具有的不稳定性、照射过程的不可重复性、待测样品基体效应的影响以及探测器产生的噪声信号干扰等多种因素，LIBS技术在实验中探测的结果标准偏差往往比较高，而使用双脉冲激光可以显著提升激发光谱的强度，进而提高探测精度和信噪比。使用飞秒激光器和双脉冲技术，会明显提高激光诱导等离子体实验的准确率和可重复性。本文由四个章节组成。在第一章里，介绍了激光诱导等离子体光谱技术的特点及其应用研究，并提出了飞秒激光诱导光谱技术和双脉冲飞秒激光诱导等离子体光谱技术；在第二章中，对激光诱导等离子体光谱技术的理论进行了系统阐述，介绍了在激光烧蚀物质等离子体光谱分析应用中常用的方法，例如等离子体电子温度的计算方法、电子密度的计算方法等；在第三章，我们在实验中应用双脉冲飞秒激光系统来诱导击穿等离子体光谱对Fe样品进行研究，对采集到的Fe等离子体光谱数据进行了分析处理，，并且选取了波长在410-445nm范围内的3条谱线，利用玻尔兹曼斜线法计算了Fe样品的等离子体电子温度，以及利用斯塔克展宽法在波长432.58nm的光谱谱线上求解了Fe等离子体电子密度，最终得到Fe样品等离子体的电子温度与延迟时间间隔、电子密度与延迟时间间隔的关系表，并得出了实验满足局部热力学平衡的依据；第四章是总结与展望，总结了实验研究的意义，并指出存在的问题以及下一步研究的方向。
[Abstract]:Laser induced breakdown spectroscopy (LIBS), as an analytical tool, has been recognized as a promising new technique since its inception. With the development of laser, spectrometer and other related instruments, ultrashort pulse laser is introduced into laser-induced plasma spectrum technology, which makes Libs technology enter the femtosecond era. The non-repeatability of the irradiation process, the influence of the matrix effect of the sample to be tested, and the noise signal interference produced by the detector, etc. The standard deviation of the results detected by the LIBS technique in the experiment is often relatively high. The intensity of excitation spectrum can be significantly increased by using double pulse laser, and the detection accuracy and signal-to-noise ratio can be improved. The accuracy and repeatability of laser-induced plasma experiments can be improved by using femtosecond laser and double pulse technique. This paper consists of four chapters. In the first chapter, the characteristics and application of laser-induced plasma spectroscopy are introduced, and femtosecond laser-induced spectroscopy and dual-pulse femtosecond laser-induced plasma spectroscopy are proposed. In this paper, the theory of laser-induced plasma spectroscopy (LIPs) is systematically described, and the methods commonly used in the analysis of laser-ablated plasma spectra, such as the calculation of plasma electron temperature, are introduced. In the third chapter, we use the double pulse femtosecond laser system to induce breakdown plasma spectrum to study the Fe sample, and analyze and process the collected Fe plasma spectral data, in the third chapter, we use the double pulse femtosecond laser system to induce the breakdown plasma spectrum to study the Fe sample. The electron temperature of Fe sample was calculated by Boltzmann slant method, and the electron density of Fe plasma was calculated by Stark broadening method on the spectral line of wavelength 432.58nm. Finally, the relation table of electron temperature and delay time interval, electron density and delay time interval of Fe sample plasma is obtained, and the basis of experimental meeting the local thermodynamic equilibrium is obtained. The significance of experimental research is summarized, and the existing problems and the direction of further research are pointed out.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN249;O562.3

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