Al等离子体特征辐射时间分辨谱线线形分析

用Nd :YAG脉冲激光烧蚀Al靶获得Al等离子体 ,利用时 空分辨技术采集Al等离子体的辐射信息 ,记录了 10～ 10 0 0 0ns延迟范围内Al等离子体辐射的时间分辨谱 ,通过分析 ,获得了Al等离子体特征谱线AlⅠ 396 15和AlⅠ 394 4 0nm的时间分辨谱。分析了 80 0～ 10 0 0 0ns延迟范围内的谱线线形 ,并分别对两条特征谱线进行了Lorentz函数和Gauss函数拟合。结果发现 ,10 0 0ns延迟以后的谱线是非常规则的Lorentz线形 ;而 10 0 0ns以前的也是Lorentz线形 ,但不十分规则 ;在该延迟范围内 ,所有时间分辨特征谱线与Gauss拟合曲线相差很大 ,说明谱线不是Gauss线形的。参照Lorentz函数拟合结果 ,测量了这两条谱线的半高全宽 ,并与谱线的自然线宽理论值比较。结果发现 ,实验值远大于理论值

Study on Time-resolved Spectra Shape of Aluminum Plasma's Characteristic Radiation

Aluminum plasma was obtained with a Nd:YAG pulsed laser beam ablating target aluminum. The radiation information of the plasma was recorded on a time and space resolution basis. So the time-resolved spectra of Al plasma were obtained with a time delay of 10 to 10,000 ns. From those spectra, we acquired the time-resolved spectra of Al I 396.15 and Al I 394.40 nm, the characteristic lines of Al plasma radiation. The shape of the two characteristic lines was studied from 800 to 10,000 ns delay. Further more, the two characteristic lines were respectively fitted in Lorentz profile and Gauss profile with Lorentz and Gauss function. As a result, all the characteristic lines after 1000 ns delay well fitted Lorentz profile, and before that time, they also fitted each other, but slightly. In the whole range of time delay, the experimental lines departed by far from the fitted Gauss profile. So we could conclude that the shape of Al I 396.15 and that of Al I 394.40 nm were all Lorentz lines, not Gauss ones. The half-high-full widths of the two characteristic lines were determined, aided with the Lorentz lines fitting. Compared with the natural widths of the two lines, the experimental results were much wider than the theoretical values.