Ultrafast dynamics of laser thermal excitation in gold film triggered by temporally shaped double pulses

•The electron excitation dynamics is proposed for explaining enhanced laser energy coupling into gold film.•The synergetic effects arising from the pulse-to-pulse relevance well explain the double-pulse energy enhancements.•The optimization of phonon thermalization process is obtained via tailoring temporally shaped femtosecond laser double pulses.

We present the theoretical studies on ultrafast thermal excitation dynamics of gold film irradiated by temporally shaped femtosecond laser double pulses. It is revealed that the gold film thermalization efficiency can be greatly promoted by optimizing the pulse energy ratio, pulse separation and pulse exchange of temporally shaped femtosecond double pulses. The phenomena are explained as the enhanced laser energy coupling into the electron subsystem due to the interplay of pulse-to-pulse energy coupling. This study should be helpful for basic understanding of the ultrafast thermal dynamics for optimizing the gold film excitation process via shaping femtosecond laser for the potential applications such as thermal plastic deformation effects, laser ablation and laser excitation spectrum.