Neutral and ion composition of laser produced lithium plasma plume in front and back ablation of thin film

Abstract

Compositional analysis of lithium plasma produced by front and back ablation of a LiF–C thin film to obtain the neutral and ionic contribution has been carried out in vacuum and at 2 × 10⁻¹ mbar argon. Temporal evolution of the ionic to neutral ratio and neutral abundance for these geometries has been estimated. For neutral abundance, two approaches are explored: Atomic Data and Analysis Structure (ADAS) analysis and integrated intensity ratio of the Li I 670.8 nm and Li I 610.3 nm lines assuming LTE conditions. We have demonstrated the precise measurement of neutral abundance irrespective of emission lines in these two geometries. We believe the present attempt will be interesting from the view point of understanding the evolution of plasma composition in various geometries/configurations of laser ablation, which has important implications in various applications e.g. pulsed laser deposition and laser cleaning.