Fundamentals of Ultrashort Pulse Laser Interactions: Mechanisms, Material Responses, and the Genesis of LIPSS

Abstract

In recent years, ultrashort pulse laser-material processing has gained significant attention due to its broad applications across nearly all manufacturing sectors. This chapter delves into the foundational aspects of the ultrashort pulse laser-material interaction and elucidates the intricacies of the underlying ablation mechanisms. Due to peculiarities between the metal energy absorption in contrast to the semiconductor or dielectric, the first section provides an in-depth exploration of laser-material dynamics, emphasizing the unique responses of various substrates under ultrashort pulse irradiation. A theoretical analysis of ultrashort laser-matter interaction can be represented by the two-temperature model, which describes the temperature of the electron or carrier and lattice in non-equilibrium conditions when ultrashort laser pulses are applied. As the narrative progresses, the spotlight shifts to one of the most interesting phenomena associated with these interactions: the formation of Laser-Induced Periodic Surface Structures (LIPSS). The second section unravels the genesis and evolution of LIPSS, demystifying LIPSS formation mechanisms and the pivotal role played by the ultrashort pulse duration.