Dynamics of supported ultrathin molybdenum films driven by strong short laser impact

Abstract

We consider expansion, break off, and flight of 10 nm molybdenum film deposited onto glass support. These events are initiated by action of subpicosecond laser pulse onto film. Approximations for two-temperature equation of state and electron--ion coupling parameter are developed. Heat conduction is unimportant because film is ultrathin and because radius of a laser beam is rather large $\sim 10$ $\mu$m (thus lateral thermal spreading is insignificant at the considered time scale). We use two-temperature one-dimensional hydrodynamic code to follow evolution of laser induced flow. Additional code for treating transmission and reflection of a monochromatic electromagnetic wave is developed. It is applied to describe interference between transmitted and reflected waves in the layered structure appearing thanks to laser induced expansion and separation of a film.