Thermal behavior of metal thin film irradiated by femtosecond double-pulse laser

The thermal behaviors of gold film under femtosecond single pulse irradiation and double pulse laser irradiation are calculated by the two-temperature equations. The temporal-spatial distributions of electron temperature and lattice temperature are obtained. At the same laser fluence, than that by the single pulse, the calculated results indicated more laser energy will penetrate into the internal target by the double pulse. The ablation depth will be enhanced. It will help us to improve the efficiency of femtosecond laser ablation of target. The evolution of first melted front is different of single pulse and double pulse ablation with different laser fluence. Near the damage threshold, the ablation depth of single pulse is greater than that of the double pulse. With increasing the laser energy density, the ablation depth of the double pulse is greater than that of the single pulse.