Ablation study in gold irradiated by single femtosecond laser pulse with electron temperature dependent interatomic potential and electron–phonon coupling factor

Abstract

The interactions of femtosecond lasers with gold targets are investigated with a numerical method combining molecular dynamics and two-temperature model and temperature dependent thermodynamic parameters. The influence of the electron temperature dependent (ETD) interatomic potential on ablation processes was analyzed. We also adopted an ETD electron–phonon coupling factor and further analyzed different ablation mechanisms under absorbed fluences ranging from Our simulation results showed good agreements on melting and ablation depth with both experiments and other simulations. Three ablation mechanisms were identified: nonthermal ablation caused by electronic pressure from the ETD interatomic potential, spallation by stresses from a rapid heating of the target and phase explosion due to explosive boiling. With a continuously updated ETD potential in accordance with electron temperature, one can explain the unique U shape profile of plume atomization degree as a function of laser fluence found in experiments.