UltrafastCARS
High-speed coherent Raman metrology for the study of transient and non-equilibrium reactive flows
Supervisor: Myriam RAYBAUT | Employer: ONERA | 3i dimension: intersectoral (interdisciplinary) 📥 ONER-3-ULTR
Contact: myriam.raybaut@onera.fr; gabi-daniel.stancu@centralesupelec.frAbstract: Femtosecond Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy allows for probing the population distribution of ro-vibrational levels in a molecular medium and thus provides a precise and non-invasive way to measure temperature within reactive media such as combustions and plasmas. To provide a new understanding of the turbulent or transient phenomena occurring in reactive flows, like rotating detonation combustions, which represent a major potential advance in aeronautical and space propulsion, or of the non-equilibrium plasmas and their related applications in energy and environment domains. ONERA is developing a very high-speed instrument based on femtosecond ultrashort laser technology. This thesis will focus in particular on optimizing light-matter interaction, developing ultrafast data processing algorithms, moceling non-equilibrium media, and experimentally validating the instrument's performance in representative flow conditions.
Project Objectives
This PhD project focuses on the development of a next-generation, high-repetition-rate CARS (Coherent Anti-Stokes Raman Scattering) instrument dedicated to the analysis of unsteady and non-equilibrium reactive flows. The research is structured around two main objectives: 1)Implementation of a new high-speed measurement system and the development of a new generation of data-processing algorithms specifically designed for high-cadence operation. 2)Extension of femtosecond CARS to non-equilibrium environments, where ro-vibrational population distributions deviate from Boltzmann statistics and follow more complex, non-thermal behaviors. Ambitious applications concern the study of Rotating Detonation Engines (RDEs)—an emerging propulsion concept that combines ultrafast transient phenomena and with highly unsteady reactive flows and non-equilibrium plasma assisted combustion & nitrogen fixation, which are relevant to the carbon-free industrial transition with a potential global impact
Specific skills and requirements
Pre-requisite: TO BE UPDATED - REFER TO PDF
Advantageous: TO BE UPDATED - REFER TO PDF
Biographies
Thesis Director Short Bio: Myriam Raybaut graduated from Ecole Supérieure d'Optique in 2003, and obtained her PhD in Physics from Université Paris XI in 2006 and her HDR in 2023. Her research interests span from non-linear optics phenomena to the development of spectrometric instrumentation. She co-authored more than 50 peer-reviewed articles and more than 107 conferences. She was awarded the Edouard Branly Prize in 2012, a Medal from the French Académie de l'Air et de l'Espace in 2014, and the Médaille de l'Aéronautique in 2023. She co-supervised 14 PhD students. She coordinated several projects, incl. two European projects. She is the head of the Laser Sources and Metrology Unit from ONERA DPHY, which deals with the development of instrumentation based on light-matter interaction for different applications, ranging from cold-atom interferometry to optical diagnostics for combustion or plasma facilities.
3i Co-supervisor Short Bio: Gabi-Daniel Stancu is a full professor at CentraleSupélec, University Paris-Saclay and the deputy director of the EM2C laboratory. His areas of expertise are in non-equilibrium plasma physics and advanced laser-based plasma diagnostics. He co-authored 50 peer-reviewed articles and more than 120 conferences. He received the French ministry of research award for scientific excellence (PEDR) in 2016 and 2020, and received the award innolec Lectureship 'Plasma spectroscopic diagnostics' incognition of the development of the teaching curricum. He coordinated several projects, including two European and 6 ANR projects. He obtained his PhD in Physics from university Ernst-Moritz-Arndt in 2004, and his HDR from université Paris Sud in 2014. He supervised 8 PhD students, and 7 post-doctoral students. By October 2026, he is expected to supervise three doctoral students (with 100%; 40% and 33%).
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