A finite difference method for studying thermal deformation in a 3D thin film exposed to ultrashort pulsed lasers

Ultrashort pulsed lasers have been attracting worldwide interest in science and engineering communities. Studying the thermal deformation induced by ultrashort pulsed lasers is important for preventing thermal damage. This article presents a new numerical method for studying thermal deformation in a 3D thin film exposed to ultrashort pulsed lasers. The method is obtained based on the parabolic two-step model and implicit finite difference schemes on a staggered mesh. It accounts for the coupling effect between lattice temperature and strain rate, as well as for the hot electron-blast effect in momentum transfer. In particular, a fourth-order compact scheme is developed for evaluating those stress derivatives in the dynamic equations of motion. The method allows us to avoid non-physical oscillations in the solution. Its performance is demonstrated by a numerical example.