Mechanism of ablation in short-pulse laser-copper target interaction

Using 1D MED101 code, the competition mechanism between nonequilibrium electrostatic field ablation and thermal equilibrium ablation was analyzed when the pulsed laser with wavelength 1 064 nm, pulse duration 1~20 ps, ablated copper in vacuum. Numerical simulation results revealed that when the pulse duration was short(1~5 ps), the nonequilibrium electrostatic field ablation occupies the ablation process, and that when the pulse duration become longer(10~20 ps), the thermal equilibrium ablation is the main process in the whole ablation. It also demonstrates that the maximum temperature of electrons versus time will have multi-peaks as the pulse duration and peak power density increase. Especially, the ablation depths of the nonequilibrium electrostatic field are 110 nm and 101 nm for pulse