UNCERTAINTY ANALYSIS OF MELTING AND RESOLIDIFICATION OF GOLD FILM IRRADIATED BY NANO- TO FEMTOSECOND LASERS USING STOCHASTIC METHOD

A sample-based stochastic model is presented to investigate the effects of uncertainties of various input parameters, including laser fluence, laser pulse duration, thermal conductivity constants for electron, and electron-lattice coupling factor, on solid-liquid phase change of gold film under nano- to femtosecond laser irradiation. Rapid melting and resolidification of a free standing gold film subject to nano- to femtosecond laser are simulated using a two-temperature model incorporated with the interfacial tracking method. The interfacial velocity and temperature are obtained by solving the energy equation in terms of volumetric enthalpy for control volume. The convergence of variance (COV) is used to characterize the variability of the input parameters, and the interquartile range (IQR) is used to calculate the uncertainty of the output parameters. The IQR analysis shows that the laser fluence and the electron-lattice coupling factor have the strongest influences on the interfacial location, velocity, and temperatures.