Spatiotemporal evolution of the morphology of multi-pulse laser ablated metals considering plasma shielding

Abstract

With the laser ablation of metals, ultrafast lasers have high peak power density and significant nonlinear absorption, but plasma shielding and large taper often exist during ablation, which seriously affects the quality and efficiency of ablation. In this paper, the heat conduction equation of the lattice system is rewritten into the dual-temperature model, the time and space terms in the femtosecond laser source equation are superimposed to calculate, and the plasma shielding effect is incorporated into the ablation model using multi-pulse laser ablation iterative calculations. The constructed 3D improved dual-temperature model uses the finite difference method to investigate the spatio-temporal evolution of the ablation morphology of the metal target under the influence of different laser parameters using the critical point phase separation mechanism. In the numerical simulation, the error of considering plasma shielding is controlled within 8.24% compared with that of not considering plasma shielding, the ablation process has obvious layering phenomenon, the actual ablation experimental results are basically consistent with the calculation results of the proposed model, and the prediction error of the ablation depth can be controlled within 13.28%, which indicates that the model proposed in this paper has the ability to more accurately describe the spatial and temporal evolution of metal ablation by femtosecond laser.