Ultrafast investigation of electron dynamics in the gold-coated two-layer metal films

The gold-coated metal thin films are widely used in modern engineering applications. In this paper, the ultrafast electron dynamics of gold-coated two-layer thin films has been investigated by ultrafast time-resolved pump–probe experiment. The dependence of the surface electron temperature on the film structure was considered based on the two-temperature model at the different two-layer film structure. The effect of laser fluence (3, 6 and 17 mJ/cm2), and two-layer film thickness (the thickness of 50 nm and 100 nm gold layer) is considered. The theoretical predictions are compared with experimental data, which agree well with both thermal model and transient reflectivity.

► The ultrafast electron dynamics of gold-coated thin films has been investigated. ► The surface electron temperature was calculated by the two-temperature model. ► The effect of laser fluence, and two-layer film thickness is considered. ► The theoretical predictions are compared with experimental data.