飞秒激光诱导Zn等离子体发射光谱时间演化特性

Time Evolution Characteristics of Zn Plasma Spectra Induced by Femtosecond Laser

利用增强电荷耦合器(ICCD)光谱探测系统对飞秒激光诱导的Zn等离子体发射光谱进行时间分辨的采集和分析,研究飞秒激光等离子体光谱及其参量的时间演化特性。分析Zn等离子体的连续谱和特征谱的谱线强度随时间的演化,发现连续谱先出现且寿命只有100 ns,随后出现特征谱,对应于不同跃迁的谱强度不同。同时由谱线的展宽和强度及其跃迁能级的相关参数等得到电子密度和温度随时间的演化规律。对谱线频移进行了分析,研究发现在等离子体膨胀初期Zn原子特征谱线(Zn I)481.0 nm的特征谱线存在较大红移,可达到0.23 nm,延时300 ns后,红移变得很小。频移随电子密度的变化近似呈线性关系。

Time-resolved spectra of Zn plasma induced by a femtosecond laser are acquired and analyzed with an intensified charge-coupled device （ICCD） spectral system. The time-evolution characteristics of the plasma spectra and parameters are investigated. Through analyzing the continuous and characteristic spectra of the Zn plasma, it is found that the continuous spectrum appears firstly and its life time is only about 100 ns, subsequently the characteristic spectrum emerges. The different characteristic spectra show different intensities. Meanwhile the evolution regularities of the electron density and temperature are obtained. Furthermore, the line shift of the spectrum at 481.0 nm is analyzed. The results show that there are red shifts for the spectrum at the original region and its maximum value is up to 0.23 nm. Then the red shift becomes quite small after 300 ns. The line shift changes with the electron density almost linearly.