ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
[en] We explore the influence of the nanoporous structure on the thermal relaxation of electrons and holes excited by ultrashort laser pulses (similar to 7 fs) in thin gold films. Plasmon decay into hot electron-hole pairs results in the generation of a Fermi-Dirac distribution thermalized at a temperature T-e higher than the lattice temperature T-1. The relaxation times of the energy exchange between electrons and lattice, here measured by pump-probe spectroscopy, is slowed down by the nanoporous structure, resulting in much higher peak T-e than for bulk gold films. The electron-phonon coupling constant and the Debye temperature are found to scale with the metal filling factor f and a two-temperature model reproduces the data. The results open the way for electron temperature control in metals by engineering of the nanoporous geometry.
[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit]
