Laser ablation of metallic targets with high fluences: Self-consistent approach

Ablation of metallic target using Gaussian profile laser pulse with duration of 30 ns and fluence extending up to 100 J/cm(2) is studied. A self-consistent model that involves numerical simulation to obtain the thickness of a hydrodynamic layer is proposed. The influence of the hydrodynamic layer thickness on Knudsen layer properties, and hence the rate of evaporation, is demonstrated. Self-consistent model is compared with model based on assumption about sonic speed at the Knudsen layer outer edge and validated with experimental results for Al alloy and Cu. Finally, sample calculations are performed using the proposed model to obtain depth of evaporation of Al alloy for single pulse duration.