Laser-solid interaction and dynamics of the laser-ablated materials

Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the thermal model with Clausius-Clapeyron equation. The vaporization temperature is determined under different surface pressure conditions. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models are coupled. The results show that lower background pressure results in lower laser energy density threshold for vaporization. The ablation rate and the amount of materials removed are proportional to the laser energy density above the threshold. A dynamic source effect is demonstrated, that accelerates the unsteady expansion of laser-ablated material in the direction perpendicular to the solid. A dynamic partial ionization effect is studied as well.