My studies were completed in 1995 at the Magistère d’Orsay of Fundamental Physics in a joined programme between Université Paris-Sud and Ecole Normale Supérieure de Cachan. During this period, I started research training on light-matter interaction: first using high intensity radiation on solid target to study the melting of matter (DGA/CREA/LALP), then at much lower intensity with photons of high energy to investigate photo-ionization process on gas phase species at the synchrotron facility LURE (Laboratoire d'Utilisation dur Rayonnement Electromagnetique, Orsay, France). I also performed numerical studies of the propagation of laser beam for the SILVA project (Separation assisted by Laser of Isotopic Atomic uranium Vapor) at a pre-industrial test facility (CEA/DCC/SPL).
Doctoral Studies: Laser spectroscopy of atoms and molecules prepared by VUV lights
In December, I had the distinction to be awarded a PhD grant from the Research and National Education Ministry in France to start experimental research at LURE under the supervision of Michael Meyer in the group of Paul Morin. The objective was to investigate in gas phase photo-ionization (and photo-fragmentation) dynamics of atoms (and molecules) developing pioneering pump-probe experiments, which combine Synchrotron Radiation or High Harmonic Generation sources with a laser. Part of the work was done in collaboration with Anne L'Huillier and Claes-Göran Wahlström at Lund University. I studied the effect of the electronic correlation on the photoionization dynamics of optically excited states in xenon and helium. Finally, I built a Laser Induced Fluorescence set-up and demonstrated the possibility to investigate photo-fragmentation dynamics by measuring the rotational structure of nitrogen molecule.
Teaching assistant and initiation to Quantum Chemistry
After I defended my PhD in June 1999, I became Attaché Temporaire d'Enseignement et de Recherche at the University of Marne-la-Vallée (France) in the Laboratoire de Chimie Théorique (LCT) under the supervision of Pavel Rosmus and Gilberte Chambaud. There, I took the unique chance offered, beside intensive teaching, to broaden my education and learn about Quantum Chemistry by performing calculations on the hydrogen cyanide cation.
Postdoctoral studies: Clusters physics
In October 2000, I started a Post-doc in the group of Stacey Sörensen and Svante Svensson at Swedish National Synchrotron Radiation Laboratory, MAX-lab, in Lund. My research activities were focused on the photo-fragmentation dynamics after inner shell excitation of gas-phase samples. Part of my role was to develop a multi-coincidence mass spectrometer together with students from Lund and Uppsala Universities. The set-up was successfully used for several studies on molecules and clusters, leading to the PhD defense of A. Lingdren.
More specifically, I studied the photo-fragmentation of argon clusters, which revealed unexpected dissociation dynamics. I found evidence for departure from pure Coulomb explosion in small clusters by identifying fragmentation patterns that depend on the photon energy, revealing the importance of nuclear motion. Although the dynamics can be understood for small systems, the complexity of dissociation increases dramatically with cluster size. I reported that medium size clusters exhibit a behavior where collective nuclear motion noticeably slows fragmentation, indicating that the ionized core is surrounded by a cooling bath made up of neutral atoms.
CNRS researcher: Double ionization
In October 2002, I joined as CNRS researcher, Chargé de Recherche de 2ème classe, the group of Alain Huetz at Orsay. My work aimed at extending the photo-double ionization studies made in the group towards: • the Coulomb explosion of the H2 molecule, prototype of the 4-body problem, • the Ionization with few-photon of atoms with High Harmonic Generation source. For this work, I upgraded first a unique reaction microscope, CIEL, with multiple-anode detector, originally developed by Michel Lavollée. I coordinated then the realization of a new multiple-anode detector and ultra-fast electronics (5 GHz) and became responsible of the development of a 3D momentum imaging experiment (CIEL2) for the High Harmonic Generation sources of the CEA-Saclay.
The studies on the H2 molecule were performed at Elettra synchrotron facility (Trieste, Italy) in collaboration with Lorenzo Avaldi, Paola Bolognesi and Tim Reddish. Our study revealed that even this simplest case of fragmentation is extremely rich in information. Electronic correlations in the electronic initial/final states and with nuclei leads to interference between outgoing partial waves in the molecular frame. The kinetic energy released provides information on the initial localization of the nuclear wave packet after ionization.
Few-photon multiple ionization of atoms is one of the most fundamental nonlinear processes, which bridges the gap between the single- and multi-photon regimes. I worked on the pioneering experiments dealing with this problem in collaboration with Pierre Agostini, Louis DiMauro, Horst Rottke and Bertrand Carré. Our main achievement was to prove the feasibility of such an experiment with monochromatic High Harmonic Ggeneration sources. These studies constituted the core of the doctoral studies of O. Guyétand.
My research activities were recognized and became Chargé de Recherche de 1ère classe, equivalent to a senior researcher title.
Lund Univsersity: From quantum mechanics to energy transfer in matter
In 2007, I realized that a transverse research approach was necessary if I wanted to meet current societal challenges such as climate change, the development of advanced materials, or energy production and storage. I took thus the opportunity to re-orient my research towards ultra-fast dynamics in small and medium size quantum systems, and started a research program that aims at understanding the interplay between light-matter interaction, photo-chemical reactions, and fundamental processes that exist in atoms, molecules and clusters.
The work is performed at Lund University in collaboration with Stacey Sörensen and Anne L’Huillier. The first phase of the project, entailed the development of state-of-the-art spectroscopic tools and methods from the AMO community (Atomic Molecular and Optical physics), such as coincidence, momentum-imaging technique and time-resolved approaches.
In 2017, Knut and Alice Wallenberg Foundation granted the project: "Attosecond chronoscopy of electron wave-packets probing entanglement and time-ordering of quantum processes", which is carried out in collaboration with Raimund Feifel.