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arXiv · 1901.01114

Pump-probe Spectroscopy Study of Ultrafast Temperature Dynamics in Nanoporous Gold

Michele Ortolani·Andrea Mancini·Arne Budweg·Denis Garoli·Daniele Brida·Francesco de Angelis
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Abstract

We explore the influence of the nanoporous structure on the thermal relaxation of electrons and holes excited by ultrashort laser pulses ($\sim 7$ 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 $T_{\mathrm{e}}$ higher than the lattice temperature $T_{\mathrm{l}}$. 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 $T_{\mathrm{e}}$ 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.

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Michele Ortolani, Andrea Mancini, Arne Budweg, Denis Garoli, Daniele Brida, Francesco de Angelis. 2019-01-04. Pump-probe Spectroscopy Study of Ultrafast Temperature Dynamics in Nanoporous Gold. https://doi.org/10.1103/physrevb.99.035435

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