Semiclassical Simulation of Laser-Electron Coupled Dynamics in Metals Under Ultrashort Pulse Laser Irradiation

Micromachining of metals using ultrashort pulse lasers has attracted significant attention, with active research being conducted both theoretically and experimentally [1], [2]. The process begins with optical electron excitation, followed by energy transfer from hot electrons to the lattice. This results in phase or structural transitions within the material, leading to material modification or removal while minimizing heat-affected zones. Plasma or continuum models are often employed to simulate ultrafast laser interactions with metals [1], [3], but these methods struggle to capture the transient dynamics before local thermodynamic equilibrium is reached. While first-principles simulations offer high accuracy, their high computational cost and inability to account for dynamic electron-electron scattering make them unsuitable for picosecond-scale simulations or laser parameter optimization. To address these computational challenges, we previously proposed a method based on the Vlasov equation [4], which provides results consistent with first-principles simulations. In this study, we extend this approach by incorporating dynamic electron-electron scattering into the Vlasov-Uehling-Uhlenbeck (VUU) equation and enhancing the model further to include light propagation via the Maxwell equation. Using this extended model, we observe that electron energy transport occurs in a laser-irradiated aluminum thin film but is suppressed by electron-electron scattering.