Theory of Non-Linear Electron Relaxation in Thin Gold Films and Their Signatures in Optical Observables

Fuente: arXiv
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Autori principali: Grumm, Jonas, Selig, Malte, Lange, Holger, Knorr, Andreas
Natura: Preprint
Pubblicazione: 2025
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author Grumm, Jonas
Selig, Malte
Lange, Holger
Knorr, Andreas
author_facet Grumm, Jonas
Selig, Malte
Lange, Holger
Knorr, Andreas
contents Based on the momentum-resolved Boltzmann equation, we provide self-consistent numerical calculations of the dynamics of conduction electrons in thin noble metal films after linear and non-linear optical excitations with infrared and terahertz frequencies. Focusing exclusively on electron-phonon interaction, orientational relaxation is introduced and acts as dephasing of the optical excitation on a scale of tens of fs. In the linear regime, our numerical results agree with the experimental fits to a Drude model and predicts for non-linear excitations a field strength dependency of the orientational relaxation rate. In the THz regime, where the orientational relaxation proceeds faster than the oscillation cycle of the excitation THz field, a new high order dissipative Kerr-type non-linearity is predicted. This non-linearity originates from the Pauli blocking included in the electron-phonon scattering and results in a non-linearly increasing transmission of the film, detectable in experiments.
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id arxiv_https___arxiv_org_abs_2504_19733
institution arXiv
publishDate 2025
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spellingShingle Theory of Non-Linear Electron Relaxation in Thin Gold Films and Their Signatures in Optical Observables
Grumm, Jonas
Selig, Malte
Lange, Holger
Knorr, Andreas
Mesoscale and Nanoscale Physics
Based on the momentum-resolved Boltzmann equation, we provide self-consistent numerical calculations of the dynamics of conduction electrons in thin noble metal films after linear and non-linear optical excitations with infrared and terahertz frequencies. Focusing exclusively on electron-phonon interaction, orientational relaxation is introduced and acts as dephasing of the optical excitation on a scale of tens of fs. In the linear regime, our numerical results agree with the experimental fits to a Drude model and predicts for non-linear excitations a field strength dependency of the orientational relaxation rate. In the THz regime, where the orientational relaxation proceeds faster than the oscillation cycle of the excitation THz field, a new high order dissipative Kerr-type non-linearity is predicted. This non-linearity originates from the Pauli blocking included in the electron-phonon scattering and results in a non-linearly increasing transmission of the film, detectable in experiments.
title Theory of Non-Linear Electron Relaxation in Thin Gold Films and Their Signatures in Optical Observables
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2504.19733