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. (C) 2001 Elsevier Science Ltd. All rights reserved.