Lagging Behavior in the Short-Pulse Laser Heating on Multi-Layered Metallic Films

The lagging behavior in a double-layered thin film subjected to femtosecond pulsed laser heating is analyzed in this work. Recently developed dual-phase-lag model is used to describe the microstructural interaction effect and the fast-transient effect of thermal inertia in the same framework. The major emphasis is placed on the appropriate thermal properties of the padding layer that renders a lowest-possible temperature-change in the surface layer that directly resists the ultrafast laser impingement. It is found that thermal diffusivity and the two phase lags in the padding layer have pronounced effect.