Molecular-dynamics study of the mechanism of short-pulse laser ablation of single-crystal and polycrystalline metallic targets

Short-pulse laser radiation focused on the surface of a material can simultaneously cause a large number of interconnected nonequilibrium processes that occur in a submicron interval within several picoseconds. Under the implemented extremal conditions, the ablation mechanism induced in a solid substance is extremely complex and has elicited numerous contradictory interpretations. A possible way to investigate its mechanism under strong nonequilibrium conditions is by using molecular dynamics. This method is used in this paper as a basis for a hybrid atomistically continuous model to describe how a picosecond laser pulse interacts with single-crystal and polycrystalline targets made from gold. The kinetics and the mechanism of induced ablation are studied. Differences are detected, and their causes are determined. (C) 2014 Optical Society of America.