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Dynamics of the radiative decay of a hot electron gas generated in the feed of an electrically-driven optical nanoantenna

ABG-78676 Sujet de Thèse
13/06/2018 > 25 et < 35 K€ brut annuel
Laboratoire Interdisciplinaire Carnot de Bourgogne
Dijon - Bourgogne-Franche-Comté - France
Dynamics of the radiative decay of a hot electron gas generated in the feed of an electrically-driven optical nanoantenna
  • Physique
  • Electronique
optical antennas, plasmonics, electromigration, tunnel junction, fluctuations, emission diagram, hot electrons

Description

The scientific program of the thesis is aimed at gaining a better understanding of the light emitted by electron-fed optical antennas. From a general point of view, optical antennas are passive nanoscale devices used to interface far-field radiation to localized electromagnetic energy and vise-versa [1]. Compared to their radiofrequency counterpart ubiquitous in our daily life, optical antennas are not generally used for transduction, but merely serve as a wave-vector converter. Nonetheless, recent developments demonstrated that optical antennas can be electrically driven, and under some conditions can operate a bilateral transduction between electrons and photons [2,3]. The asset of such novel class of active optical antenna is their ability to be deployed as ultrafast nanoscale interface devices. They can be used to interconnect an electronic control layer and a photonic circuitry.  In this proposal the focus is made on the electron-to-photon transduction. When electrically biased, optical antennas emit a broadband light spectrally tailing in the visible part of the spectrum. Different emission mechanisms are at play including inelastic electron tunneling and thermal relaxation of an out-of-equilibrium electron distribution.

The thesis will investigate the time dynamics and statistics of the photons generated by the optical antenna when electrons are injected. In the context of a nanoscale light-emitting device involved in an integrated protocol of signal transmission [4], encoding the information is critical. The first objective is to assess how fast the emitted light can be modulated by an electrical command. The thermal relaxation of the electron gas is a fast process in metals, which enables an intrinsic ultrafast response of the optical antenna (ps) that will be characterized during the thesis. The second objective is the shaping of the emission diagram. The light emitted typically covers the visible to the near-infrared spectral region. An engineering of the bandwidth requires a structuration of the electromagnetic environment in which the radiation is emitted. The candidate will therefore integrate the optical antenna into resonant structure and investigate the coupling mechanisms between the modal landscape and the energy of the photons set by the applied bias.

[1] Antennas for light, L. Novotny & N Van Hulst, Nature Photonics 5 83 (2011)

[2]Spontaneous Hot-Electron Light Emission from Electron-Fed Optical Antennas, M. Buret et al. Nano Lett., 15, 5811-5818 (2015)

[3] Nonlinear Photon-Assisted Tunneling Transport in Optical Gap Antennas, A. Stolz et al. Nano Lett., 14, 1-25 (2014)

[4] Optical wireless link between a nanoscale antenna and a transducing rectenna, A. Dasgupta et al. Nature Commun., 9, 1992 (2018)

Nature du financement

Contrat doctoral

Précisions sur le financement

Région de Bourgogne Franche-Comté

Présentation établissement et labo d'accueil

Laboratoire Interdisciplinaire Carnot de Bourgogne

Le Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Unité Mixte de Recherche CNRS, Université de Bourgogne et Université de Technologie Belfort-Montbéliard, compte 300 physiciens, chimistes, Ingénieurs et Techniciens implantés en Bourgogne-Franche Comté, sur les sites de Dijon, Le Creusot, Châlon-sur-Saône & Belfort (Sévenans). Ils développent de nouvelles fonctionnalités pour l'optique et les nouveaux matériaux, à destination d'applications dans l'industrie, la médecine et les télécommunications.

Intitulé du doctorat

Doctorat de Physique

Pays d'obtention du doctorat

France

Etablissement délivrant le doctorat

Université de Bourgogne Franche-Comté

Ecole doctorale

Carnot

Profil du candidat

A Master in optics, electronics, or mesoscopic physics. Nanofabrication and characterization techniques will be subject to specific trainings. This research program requires a profound taste for complex experiments. Curiosity, personal investment and team spirit are essential.

Date limite de candidature

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