Jury members:

Andrea Bragas, Universidad de Buenos Aires, Rapportrice

Sebastian Volz, LIMMS - University of Tokyo, Rapporteur

Juan Ariel Levenson, C2N/CNRS, Examinateur

Anthony Kent, University of Nottingham, Examinateur

Samuel Raetz, LAUM - Le Mans Université, Examinateur

Daniel Lanzillotti-Kimura, C2N/CNRS, Directeur de thèse

Pascale Senellart, C2N/CNRS, Co-encadrante

Abstract:

Phonons are quasi-particles relatively unexploited for application purposes, in comparison with electrons and photons. GaAs/AlAs heterostructures like superlattices have been established as a platform that allows engineering the propagation and confinement of acoustic phonons in nanostructures. In this work, we introduce novel devices that control the propagation of acoustic waves and, furthermore, allow us to study and mimic solid-state physical phenomena of different nature. Superlattices also offer the possibility  to enhance the transduction of acoustic phonons into optical signals. Nowadays, there exists a demand for novel techniques that facilitate the experimental study of nanophononic devices. In the course of this thesis, we have experimentally studied nanoengineered GaAs/AlAs heterostructures that control the propagation of coherent acoustic phonons in the tens to hundreds of gigahertz range. We develop novel experimental techniques based on the use of single-mode fibers and pump-probe spectroscopy that allow us to identify the presence of coherent phonons with unprecedented robustness and reproducibility.

Visio link: https://us02web.zoom.us/j/85202959302

Find a clickable link in the attached file below

Members of the jury:

Mme Beatrice DAGENS - Thesis director Université Paris-Saclay (C2N), France.

M. Vladimir BELOTELOV - Reporter :  Lomonosov Moscow State University, Russia.

M. François ROYER - Reporter :  Université Jean Monnet Saint-Étienne (LabHC), France.

Mme Giovanna CALO - Examinator :  Politecnico di Bari (DEE), Italy.

M. Mathias VANWOLLEGHEM - Examinator :  Université Lille 1 (IEMN), France.

M. Eric CASSAN - Examinator : Université Paris-Saclay (C2N), France.

M. Giovanni MAGNO - Examinator :  Politecnico di Bari (DEE), Italy.

M. Alexandre Shen - Invited : III-V Lab, France.

Abstract:

Integrated optical isolators are nonreciprocal components which are crucial for complex Photonic Integrated Circuits, in order to protect laser sources from reflected signals. Our aim is to develop isolator structures in waveguiding configuration which are based on the intertwined effects of magneto-optics and plasmonics. Such a system exploits on one hand magneto-optical (MO) effects to provide nonreciprocal functionality and on the other hand, propagating surface plasmons to enhance these nonlinear effects and contribute to the miniaturization of the device.  Two different magnetoplasmonic isolator geometries are studied thoroughly in this thesis. The first is a resonant device consisting of a MO waveguide side coupled to a nanostructured gold grating. The second is non-resonant and is based on the asymmetric plasmonic mode of a MO slot waveguide. In both cases, high values of isolation ratio and figure of merit are predicted with a respectable bandwidth of operation.

Lien visio: https://eu.bbcollab.com/guest/daaf7e27ea9c41afab06ee984b7b2922

Find a clickable link in the attached file below