Multi-species temperature and number density analysis of a laser-produced plasma using dual-comb spectroscopy

Dual-comb spectroscopy (DCS) represents a novel method of using absorption spectroscopy as a diagnostic tool for multispecies analysis of excitation temperatures and column densities in laser-produced plasmas (LPPs). DCS was performed on a LPP generated by ablating a multielement alloy containing Nd, Gd, and Fe. Transitions from all three elements were observed in absorption spectra measured from 530.08 to 535.19 nm at seven time-delays from 31 to 250 mu s after ablation. The spectra were fit using a nonlinear regression algorithm to determine peak areas, and excitation temperatures and column densities were determined for the three atomic species separately using Boltzmann plots. The measured excitation temperatures of Nd I and Gd I showed good agreement at all time-delays, whereas the Fe I temperature was found to be higher, and the ratios between the column densities varied with delay. The observations are understood via effects of LPP spatial averaging, elemental fractionation, and molecular formation and are compared and contextualized with previous work studying LPPs using other spectroscopic techniques. A brief discussion of the precision and accuracy of the determined excitation temperatures and column densities is also presented. Published under an exclusive license by AIP Publishing.

Automated summary

Dual-comb spectroscopy (DCS) is a novel diagnostic tool for analyzing excitation temperatures and column densities in laser-produced plasmas (LPPs). In this study, DCS was used to measure the excitation temperatures and column densities of Nd, Gd, and Fe in a multielement alloy. The results showed that the excitation temperatures of Nd I and Gd I were consistent at all time-delays, while the Fe I temperature was higher and the column density ratios varied with delay.