We explore the influence of the nanoporous structure on the thermal relaxation of electrons and holes excited by ultrashort laser pulses (∼7fs) in thin gold films. Plasmon decay into hot electron-hole pairs results in the generation of a Fermi-Dirac distribution thermalized at a temperature Te higher than the lattice temperature Tl. 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 Te 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.
Pump-probe spectroscopy study of ultrafast temperature dynamics in nanoporous gold / Ortolani, Michele; Mancini, Andrea; Budweg, Arne; Garoli, Denis; Brida, Daniele; de Angelis, Francesco. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 99:3(2019). [10.1103/PhysRevB.99.035435]
Pump-probe spectroscopy study of ultrafast temperature dynamics in nanoporous gold
Ortolani, Michele
;Mancini, Andrea;
2019
Abstract
We explore the influence of the nanoporous structure on the thermal relaxation of electrons and holes excited by ultrashort laser pulses (∼7fs) in thin gold films. Plasmon decay into hot electron-hole pairs results in the generation of a Fermi-Dirac distribution thermalized at a temperature Te higher than the lattice temperature Tl. 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 Te 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.File | Dimensione | Formato | |
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