We aim at measuring ultrafast processes in atoms, molecules, and solids using innovative spectroscopic techniques based on high-order harmonics, strong-field driven attosecond electron wavepackets, XUV angle-resolved photoemission spectroscopy, as well as fs-REMPI (resonant enhanced multiphoton ionization) using velocity map imaging, COLTRIMS, and Momentum microscopy detection schemes. These research interests lead us to develop theoretical tools to describe the main steps of undergoing pump-probe experiments.
The HarMoDyn team is located in the laboratory CEntre Lasers Intenses et Applications (CELIA - CNRS UMR 5107) at Universite de Bordeaux, 351 Cours de la Libération, 33405 TALENCE CEDEX, France.
CELIA facilities are accessible through the national LOA-LIDYL-CELIA call, and via LASERLAB Europe.
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UTOPIQ One of our main research interests is the investigation of ultrafast light-induced dynamics in quantum materials using time-, angle-, and polarization-resolved photoemission spectroscopy. This is the goal of the UTOPIQ project - Ultrafast Topological Engineering of Quantum Materials - funded by the European Research Council (ERC) Starting Grant (StG). This project aims at developing innovative measurement protocols in multidimensional photoemission spectroscopy to probe ultrafast out-of-equilibrium topological phase transitions in two-dimensional quantum materials. |
Highlights
Ultrafast Spin Dynanics
With our colleagues from CY Cergy Paris Université, Université Paris-Saclay, Chinese Academy of Sciences, and the University of West Bohemia, we have successfully manipulated the electron's spin in a two-dimensional solid using circularly polarized light and measured its ultrafast relaxation dynamics on femtosecond timescale using spin-, time- and angle-resolved photoemission spectroscopy.
INP's News (CNRS - Institute of Physics):
https://www.inp.cnrs.fr/fr/cnrsinfo/controler-la-dynamique-ultrarapide-du-spin-de-lelectron
The article:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.066402
Electrons filming themselves
Strong laser fields enable taking snapshots of a molecule using its own electrons. The electrons are ionized from the molecule, accelerated by the laser field and driven back to recombine with their parent ion, emitting a flash of light which encodes the molecular structure. We have performed an experiment in which two consecutive sets of electrons probe the same molecule, providing two snapshots separated by a few hundreds attoseconds. Comparing these two snapshots reveals the dynamics of the molecule in the strong laser field.
Viewpoint in Physics:
https://physics.aps.org/articles/v16/27
The article:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.083201
Electrons on the run
Will an electron escaping a molecule through a quantum tunnel behave differently depending on the left- or right-handedness of the molecule?
https://phys.org/news/2022-12-electrons-chirality-tunneling-fields.html
A new observable in ARPES
We introduced a novel measurement methodology and associated observable in extreme ultraviolet (XUV) angle-resolved photoemission spectroscopy (ARPES), based on continuous modulation of the ionizing radiation polarization axis. Tracking the energy- and momentum-resolved amplitude and phase of the photoemission intensity modulation upon polarization axis rotation allows us to retrieve the circular dichroism in photoelectron angular distributions (CDAD) without using circular photons, providing direct insights into the phase of photoemission matrix elements.
Photoelectron Elliptical Dichroism Spectroscopy
When chiral molecules are ionized by elliptically polarized laser pulses, a strong forward/backward asymmetry appears in the angular distribution of the photoelectrons. In this recent article published in PCCP, we use this PhotoElectron Elliptical Dichroism (PEELD) as a spectroscopic tool to investigate the influence of different Rydberg states in the resonance-enhanced multiphoton ionization of fenchone by tunable femtosecond pulses.
