Ab initio-simulated optical response of hot electrons in gold and ruthenium.

Optical femtosecond pump-probe experiments allow to measure the dynamics of ultrafast heating of metals with high accuracy. However, the theoretical analysis of such experiments is often complicated because of the indirect connection of the measured signal and the desired temperature transients. Establishing such a connection requires an accurate model of the optical constants of a metal, depending on both the electron temperature T and the lattice temperature T.

Effect of Atomic-Temperature Dependence of the Electron-Phonon Coupling in Two-Temperature Model.

Ultrafast laser irradiation of metals can often be described theoretically with the two-temperature model. The energy exchange between the excited electronic system and the atomic one is governed by the electron-phonon coupling parameter. The electron-phonon coupling depends on both, the electronic and the atomic temperature.