Ultrafast thermalization dynamics in two-layer metal films excited by temporally shaped femtosecond laser

We theoretically investigated ultrafast thermalization dynamics in two-layer Au coated metal films excited by temporally shaped femtosecond laser. It is revealed that the thermalization processes at surface and interface of the two-layer metal films can be alternatively promoted via tailoring pulse separation and pulse energy ratio of temporally shaped double pulses. The results are explained as competitive electron–phonon coupling dynamics in the two-layer metal films, which can be well manipulated by temporally shaped femtosecond laser. This study provides basic understanding for optimizing laser thermal damage in layered metal films via tailoring femtosecond laser for a wide range of applications in the fields such as laser resonant cavity, photoelectric equipments, MEMS and biochips.