Ultrafast Phenomena in Copper Films

Abstract

The investigation of ultrafast processes in copper films by femtosecond pump-supercontinuum probe laser spectroscopy is presented. The energy dependence of electron-electron and electron-phonon scattering rates in wide spectral region of probing 1.6 < ℏωprobe < 3.2 eV is clearly observed. It is shown that the relaxation rates sharply slow down in the spectral area, related to the optical transitions into the vicinity of the Fermi level. The position of rate minimum gives the location of the Fermi level. The rate energy dependence around minimum gives unique information on the quasiparticle damping rate near the Fermi surface and thus on the Fermi liquid vs non-Fermi liquid behavior.