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

Abstract

In this article, we report rather long time emission (∼250 μs) from aluminum neutrals (Al I) in a ns laser-produced plasma in the presence of ambient argon. The study is carried out with varying laser power density, background pressure, and 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.