Theoretical investigation of laser pulse width dependence in a thermal confinement regime

Previous molecular dynamics (MD) simulations of ultraviolet (UV) laser ablation demonstrate the distinct dependence of material ejection on laser fluence and laser pulse duration. In this paper, we examine the pulse width dependence when the laser pulse widths are appropriate for the thermal confinement regime. We perform MD simulations of laser ablation with a laser pulse duration of 1 ns and compare with a pulse width of 150 ps as in previous simulations. The simulations confirm that the pulse width in thermal confinement regime does not dramatically influence the molecular ejection mechanism. The simulations reveal differentiations, however, in plume composition and the ablation threshold value. PACS 02.70.Ns; 61.80.Az; 79.20.Ap