Modeling of ultrashort laser pulse-train processing of metal thin films

The improved two-temperature model with quantum treatments is used to analyze the ultrashort laser pulse-train processing of gold thin films. This study demonstrates that (1) as compared to “normal” laser heating, pulse-train technology can increase the photon efficiency, i.e., less total laser energy is required to achieve the same lattice temperature or phase change; (2) the number of bursts required for melting decreases with the repetition rate, but at tens of MHz or higher, the repetition rate has a negligible effect; (3) the lattice temperature at the thermolization time first increases to a peak and then decreases as the pulse separation time increases.