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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 acquisition and analysis of femtosecond laser-induced Zn plasma emission spectra were performed using an Enhanced Charge Coupled Spectrometer (ICCD) spectral detection system to study the temporal evolution characteristics of the femtosecond laser plasma spectrum and its parameters. The evolution of the spectral intensity of the continuous spectrum and the characteristic spectrum of Zn plasma over time was analyzed. It was found that the continuum appeared first with a lifetime of only 100 ns, followed by the appearance of a characteristic spectrum corresponding to different spectral intensities of different transitions. At the same time, the evolution of electron density and temperature with time are obtained from the broadening and intensity of spectral lines and the related parameters of their transition levels. The spectral shift is analyzed. It is found that there is a large red shift at the characteristic wavelength of 481.0 nm for the Zn atomic signature (Zn I) at the initial stage of plasma expansion, reaching 0.23 nm. After a delay of 300 ns, the red shift Very small. The frequency shift is approximately linear with the change of electron density.