Surface thermal expansion of metal under femtosecond laser irradiation

Abstract
Transient surface displacement of gold under femtosecond laser irradiation is studied using a probe beam deflection technique. A surface thermal expansion rise time of about 100 ps is explained in terms of nonequilibrium diffusion and thermalization of photoexcited electrons. Transient displacement provides direct information on the lattice temperature profile established once the electron-lattice relaxation is completed.