Thermal effects in femtosecond laser ablation of metals

Abstract

With recent advances in ultrafast laser technology, ablation using femtosecond laser pulses has found a wide range of applications. It is widely believed that ablation using femtosecond lasers has many unique advantages compared to longer-pulse ablation. One of the most significant features is believed to be that a negligible amount of energy should remain in the sample following ablation because the deposited heat does not have enough time to travel into the bulk sample during the femtosecond laser pulse. In this paper, we discuss our new findings on thermal effects in femtosecond laser ablation of metals. In contrast to the previous common belief, we find that a significant amount of residual thermal energy is deposited in metal samples following multi-shot femtosecond laser ablation. We further discuss how the absorptance of metals depends on the structural modifications. Lastly, we discuss the formation of periodic surface structures on metals induced by femtosecond laser pulses.