Temperature-dependent thermal lagging in ultrafast laser heating

Temperature-dependent phase-lags are incorporated in the dual-phase-lag (DPL) model to fully describe the experimental data of femtosecond (fs) laser heating on gold films of various thicknesses in the sub-micron range. An explicit finite difference algorithm is developed to perform the nonlinear analysis, which recovers the Crank–Nicholson stability criterion in the special case of Fourier diffusion. The exponents in the temperature-dependent thermal properties are determined by minimizing the mean error between the numerical and the experimental results. The lagging model with temperature-dependent thermal properties enables a consistent description of all the available experimental data for ultrafast laser heating on gold films.