Investigation of Laser Produced Plasma Expansion in Ambient Gases for Aluminum and Silicon

Laser ablation is a complex field of physics, covering many different physical processes including laser absorption, phase transformations, and plasma expansion. Although various experiments and modeling techniques have been developed to investigate the laser ablation process, further studies are necessary to understand the interaction of the expanding plasma with an ambient gas. In order to better understand this process, we studied the expansion of a laser produced plasma into air and argon at atm. pressure. 1064 nm, 6 ns pulses from an Nd:YAG laser at radiation intensities up to 10 GW/cm2 were used to generate aluminum and silicon plasmas. The dynamics of the shockwave propagation and plasma expansion following laser ablation were studied using shadowgraphy and ICCD imaging. Additionally, the electron density and electron temperature of the plasma were measured using spectroscopy. The results were then compared to those obtained from computational models and the discussion delves into the accuracy of these models.