A comprehensive study on the line profiles and Stark widths of ionic transitions from laser-produced aluminum plasma

Abstract

We present a systematic spectroscopic investigation of laser-produced aluminum plasma to address inconsistencies in Stark broadening parameters and establish a self-consistent reference data sets for electron density diagnostics. Optical line emissions of Al II and Al III in the visible wavelength range were recorded from plasmas having different electron densities and temperatures, however, with the same experimental configuration, only by varying the background pressure, spatial position, and delay time. The Stark width parameter of Al III lines, which shows consistency across different earlier studies, is used for standardizing the Al II transition from the highest energy level, which is abundant in the emission spectra. This reference spectrum is then used to estimate the Stark parameters of other Al II transitions to obtain a self-consistent database for Al II transitions. This approach significantly reduces the uncertainty in the estimated plasma electron density using Stark parameters of multiple emission lines. We also report the spatial and temporal evolution of plasma density and Stark shift as well as asymmetry in spectral lines. This work addresses the uncertainty in Stark parameters of Al II transitions in the visible range through a unified approach in estimating these parameters simultaneously.