Femtosecond studies of nonequilibrium electronic processes in metals

High-intensity femtosecond laser pulses are used to induce non- equilibrium electron heating in gold metal. The thermal relaxation of the electronic distribution is studied through pump and continuum probe measurements of transient reflectivity. Measurements are performed for different heating-pulse fluences and probe-photon energies. The observed reflectivity line shape demonstrates the generation of nonequilibrium electron temperatures which cool to the lattice on a 2--3 ps time scale.