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Impact of the terahertz and optical pump penetration depths on generated strain waves temporal profiles in a V 2 O 3 thin film

Authors :
Guénolé Huitric
Michael Rodriguez-Fano
Lucas Gournay
Nicolas Godin
Marius Hervé
Gaël Privault
Julien Tranchant
Zohra Khaldi
Marco Cammarata
Eric Collet
Etienne Janod
Christophe Odin
Institut de Physique de Rennes (IPR)
Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Institut des Matériaux Jean Rouxel (IMN)
Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST)
Nantes Université - pôle Sciences et technologie
Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie
Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN)
Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)
Dynamical Control of Materials (DYNACOM)
Centre National de la Recherche Scientifique (CNRS)
The University of Tokyo (UTokyo)
The authors gratefully acknowledge Agence Nationale de la Recherche for financial support under grant, ANR-19-CE30-0004 ELECTROPHONE, ANR-19-CE29-0018 MULTICROSS, the University Rennes 1 and CNRS Human Resources Direction, for funding.
ANR-19-CE30-0004,ELECTROPHONE,Transitions de phase ELECTROnique de matériaux moleculaires controllées par PHONONIQUE non-linéaire(2019)
ANR-19-CE29-0018,multicross,Trajectoires multiples vers les états excités(2019)
Source :
Faraday Discussions, Faraday Discussions, 2022, ⟨10.1039/D2FD00013J⟩
Publication Year :
2022
Publisher :
HAL CCSD, 2022.

Abstract

International audience; Triggering new stable macroscopic orders in materials by ultrafast optical or terahertz pump pulses is a difficult challenge, complicated by the interplay between multiscale microscopic mechanisms, and macroscopic excitation profiles in samples. In particular, the differences between the two types of excitations are still unclear. In this article, we compare the optical response on acoustic timescale of a V2O3 Paramagnetic Metallic (PM) thin film excited by a terahertz (THz) pump or an optical pump, at room temperature. We show that the penetration depth of the deposited energy has a strong influence on the shape of the optical transmission signal, consistent with the modulation of permittivity by the superposition of depth-dependent static strain, and dynamical strain waves travelling back and forth in the sample layer. In particular, the temporal modulation of the optical transmission directly reflects the excitation profile as a function of depth, as well as the sign of the acoustic reflection coefficient between the film and the substrate. The acoustic mismatch between the V2O3 layer and the substrate was also measured. The raw data were interpreted with a one-dimensional analytical model, using three fitting parameters only. These results are discussed in the context of triggering phase transitions by ultrafast pump pulses. To the best of our knowledge, this is the first report of the modulation of the optical transmission of V2O3 with a THz pump within the acoustic timescale.

Details

Language :
English
ISSN :
13596640 and 13645498
Database :
OpenAIRE
Journal :
Faraday Discussions, Faraday Discussions, 2022, ⟨10.1039/D2FD00013J⟩
Accession number :
edsair.doi.dedup.....785381e1ab9936ec1696ec890c71d746
Full Text :
https://doi.org/10.1039/D2FD00013J⟩