[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.