Ultrashort (10 fs-100 ps) pulse laser ablation of pure silicon in vacuum was simulated by using a modified self-consistent one-dimensional hydrodynamic code to study the fundamental ablation mechanisms. The presented results provide a guide for drilling periodic microholes or microgratings on the dense insulator surface. The simulated laser ablation threshold remains nearly constant in femto-second regime, and increases as the square root of pulse duration in picosecond regime. The ablation depth as a function of pulse duration shows four different regimes and the ablation depth reaches a minimum when the pulse duration is similar to 30 ps at various laser fluences. The influence of laser-induced plasma shielding on ablation depth was also studied.

Hydrodynamic simulation; Laser silicon ablation; Ultrashort laser

Harbin Institute of Technology