On the delayed emission from laser produced aluminum plasma under argon environment

TL;DR

This study reports a long-lasting delayed emission from aluminum neutrals in laser-produced plasma within an argon environment, influenced by experimental conditions, likely due to energy transfer from metastable argon states.

Contribution

First observation of long delayed emission (~250 μs) from aluminum neutrals in laser plasma under argon, highlighting the role of ambient gas metastables.

Findings

Delayed emission depends on laser power, distance, and pressure.

Emission is exclusively from aluminum neutrals.

Energy transfer from argon metastables likely causes the delayed emission.

Abstract

In this article, we report rather long time emission ($\sim$ 250 $\mu s$) from aluminum neutrals (Al I) in ns laser produced plasma in the presence of ambient argon. The study is carried out with varying laser power density, background pressure, and the distance from the target. Slow and fast peak components in the emission spectra observed at earlier times are well reported. However, interestingly a very long delayed emission is also observed for the first time which depends on laser power density, distance from the target, ambient gas and pressure. The emission is observed from Al neutrals only. The most likely mechanism of this emission appears to be the excitation and subsequent emission from Al neutrals as a result of energy transfer from metastables of the ambient gas.