双飞秒激光脉冲诱导击穿光谱增强特性研究  

Enhanced laser-induced breakdown spectroscopy on Co sample with double femtosecond laser pulses

作　　者：吴柯岩 任忠国[1] 苏容波[1,2] 刘小亮[1] 沈洁[1] 胡碧涛[1] 

机构地区：[1]兰州大学核科学与技术学院,兰州730000 [2]中国工程物理研究院核物理与化学研究所,四川绵阳621900

出　　处：《强激光与粒子束》2016年第8期35-39,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(11135002);科学技术部国际科技合作与交流项目(S2012ZR02850)

摘　　要：在大气环境中,以钴为样品,通过单脉冲飞秒激光诱导击穿光谱及共轴双飞秒脉冲激光诱导击穿光谱的对比实验,研究了双脉冲激光诱导击穿光谱的谱线增强机制,测量了双脉冲激光诱导击穿光谱随脉冲时间间隔的变化趋势。结果表明,在最优化的脉冲时间间隔条件下,双脉冲激光诱导等离子体光谱获得明显增强。进一步,通过线性Boltzmann法得出了电子温度随脉冲时间间隔的演化,发现了谱线增强因子和电子温度随脉冲时间间隔呈现出相同的演化趋势,并经历两个明显的变化过程,得出了谱线信号强度的增强依赖于电子温度升高的结论。This paper presents the study on the enhancement mechanism of laser-induced breakdown spectroscopy on cobalt sample with double femtosecond pulse.The double-pulse experiments were carried out in the collinear beam geometry in air.The influence of the delay between the two collinear laser pulses was investigated by changing the pulses＇ path length.In cases of no delay between the two pulses,the laser-induced breakdown spectroscopy is equivalent to that induced by a single pulse laser with energy equals to the sum of the double collinear pulse energy.The obtained results show that with an optimized delay,the doublepulse laser-induced breakdown spectroscopy has a very clear enhancement comparing with the single-pulse laser induced breakdown spectroscopy.In addition,the dependence of the electron temperature obtained by linear Boltzmann method on the pulse interval was investigated.The experiment shows that the dependence of spectral enhancement factor on the pulse interval is the same as that of the electron temperature,both of them go through two obvious changing processes.Analysing by the Boltzmann equation,we draw the conclusion that the spectral signal enhancement depends on the electron temperature.

关 键 词：飞秒激光 双脉冲 增强因子 电子温度 

分 类 号：O433.1[机械工程—光学工程] O536[理学—光学]