AN AXISYMMETRIC MODEL FOR SOLID-LIQUID-VAPOR PHASE CHANGE IN THIN METAL FILMS INDUCED BY AN ULTRASHORT LASER PULSE

摘要

An axisymmetric model for thermal transport in thin metal films irradiated by an ultrashort, Gaussian laser pulse was developed. The superheating phenomena including preheating, melting, vaporization and re-solidification were tracked, modeled and analyzed. The temperature-dependent thermal characteristics and electron-lattice coupling factor were incorporated in the numerical analysis. Together with the energy balance, nucleation dynamics was employed iteratively to track the solid-liquid interface and the gas kinetics law was used iteratively to track the liquid-vapor interface. The numerical results showed that higher laser fluence and shorter pulse width lead to a higher temperature distribution, higher interfacial temperature, and larger melting and ablation depths. A simplified 1-D model could overestimate temperature response and ablation depth?due to the fact that radial heat conduction is neglected.