Subpicosecond Spectroscopic Ellipsometry of the Photoinduced Phase Transition in VO<sub>2</sub> Thin Films
We report the first application of broadband time-resolved pump-probe ellipsometry to study the ultrafast dynamics of the photoinduced insulator-to-metal transition (IMT) in vanadium dioxide (VO<sub>2</sub>) thin films driven by 35 fs laser pulses. This novel technique enables the direct measurement of the time-resolved evolution of the complex pseudodielectric function of VO<sub>2</sub> during the IMT. We have identified distinct thermal and nonthermal dynamics in the photoinduced IMT, which critically depends on the pump wavelength and fluence, while providing a detailed temporal and spectral phase map. A comparison of the pseudodielectric function of the VO<sub>2</sub> thin film during thermally and photoinduced phase transitions reveals that the primary differences in the IMT pathways occur within the first picosecond after the pump, driven by nonequilibrium dynamics in this ultrafast time scale. The ultrafast spectroscopic ellipsometry introduced in this work offers a complementary probe to study phase changes in condensed matter and emerging photonic device materials.
Authors
- Shriram Ramanathan (ORCID: https://orcid.org/0000-0002-6685-6798)
- Sébastien Cueff (ORCID: https://orcid.org/0000-0002-8668-2633)
- Krishna Khakurel (ORCID: https://orcid.org/0000-0001-5974-8302)
- Saúl Vázquez-Miranda (ORCID: https://orcid.org/0000-0001-9897-5508)
- Shirly Espinoza (ORCID: https://orcid.org/0000-0002-2740-7156)
- Mateusz Rębarz (ORCID: https://orcid.org/0000-0002-5823-2432)
- J. M. Saiz (ORCID: https://orcid.org/0000-0003-3713-9877)
- Yael Gutiérrez (ORCID: https://orcid.org/0000-0002-1604-7968)
- Zhen Zhang (ORCID: https://orcid.org/0000-0002-1188-5209)
Institutions
- Université Claude Bernard Lyon 1 (FR)
- École Centrale de Lyon (FR)
- Centre National de la Recherche Scientifique (FR)
- Universidad de Cantabria (ES)
- Purdue University West Lafayette (US)
- Institut des Nanotechnologies de Lyon (FR)
- Extreme Light Infrastructure Beamlines (CZ)
- Institute of Condensed Matter Chemistry and Technologies for Energy (IT)
- Institut National des Sciences Appliquées de Lyon (FR)
- École d'Ingénieurs en Chimie et Sciences du Numérique (FR)
Publication Details
- Journal
- ACS Photonics
- Published
- 2024-10-10
- DOI
- https://doi.org/10.1021/acsphotonics.4c01414
- Citations
- 7
- Primary Topic
- Transition Metal Oxide Nanomaterials
- Type
- article
- Field-Weighted Citation Impact
- 1.18
Funders
- Ministerio de Ciencia, Innovación y Universidades
- European Commission
- Agence Nationale de la Recherche
- Akademie Věd České Republiky
- Air Force Office of Scientific Research