Description du sujet de thèse

Title: Development of an Optical Testbed for the MADWIL Doppler Lidar to Measure Martian Winds
Project Overview
Understanding the dynamics of the Martian atmosphere remains one of the major frontiers in planetary science. Although Mars has been observed from orbit and on the surface for nearly five decades, its winds have never been systematically measured. Yet atmospheric circulation drives nearly every climatic and geological process on the planet—from dust storms and aeolian erosion to the transport of water vapour, clouds and trace species.
The lack of direct wind measurements is now recognised as a key limitation in advancing Mars Global Climate Models and in interpreting the planet's past climatic evolution.
To close this gap, the European Space Agency (ESA) is preparing the ZefERO orbital mission. A central element of its proposed payload is MADWIL (Mars Atmospheric Doppler Wind Interferometer Lidar), a pioneering Doppler wind lidar designed to measure horizontal winds across the entire Martian atmosphere with ~1 km vertical resolution on a global scale. Its scientific potential is comparable to that of ESA's ADM-Aeolus, which transformed wind profiling on Earth.
MADWIL retrieves winds from the backscattering of ubiquitous Martian dust. The Doppler shift is analysed using a four-channel Quadri Mach–Zehnder (QMZ) interferometer—an approach developed and refined at LATMOS over several decades.
About the PhD Project
Before the instrument can be finalised for flight, a representative optical testbed must be developed to validate its core measurement principles and assess its performance under Mars-analog conditions.
The PhD student will take a leading role in designing, assembling, and characterising this testbed within the lidar development team at LATMOS.
This experimental platform will be central to the technical maturation of MADWIL and will directly inform ESA's decision-making for the ZefERO mission.
Key Objectives
• Develop a complete laboratory optical testbed representative of the MADWIL Doppler channel.
• Validate the performance of the QMZ interferometer and the overall optical architecture.
• Quantify the instrument's sensitivity to weak, dust-like backscatter levels typical of the Martian troposphere.
• Provide engineering and scientific inputs for the future flight instrument.
Project Tasks
1. Optical design and modelling
• Translate Mars atmospheric and scientific requirements into technical specifications.
• Model the Doppler measurement chain (laser, optics, fibre injection, QMZ, detectors).
• Design the testbed architecture, including a 532 nm laser source and a Martian backscatter simulator.
2. Laboratory implementation
• Assemble and align the full optical bench.
• Develop or integrate a low-signal backscatter simulator representative of Martian aerosols.
• Integrate the QMZ interferometer and ensure mechanical and thermal stability.
3. Performance characterisation
• Measure Doppler sensitivity, interference contrast, and phase stability.
• Assess performance in low-flux, photon-noise-dominated conditions analogous to Mars.
• Conduct tolerance analyses, especially regarding optical misalignments.
4. Dissemination and contribution to the mission
• Present results to CNES, ESA, and industrial partners (Airbus, Winlight Optics).
• Contribute to conferences in atmospheric remote sensing and planetary science.
• Prepare at least one peer-reviewed publication on the validation of the MADWIL concept.
Candidate Profile
We welcome applications from highly motivated candidates with:
• A Master's degree (or equivalent) in optics, photonics, physics, engineering, or a related field.
• Strong interest in planetary exploration, atmospheric dynamics, and space instrumentation.
• Experience in optical alignment, lasers, fibre optics, or low-flux detection is a strong asset.
• Skills in modelling and scientific computing (Python, Matlab, etc.).
• A rigorous, hands-on approach and enthusiasm for working within an interdisciplinary team.

Contexte de travail

The PhD will be carried out at LATMOS (Laboratoire Atmosphères, Milieux, Observations Spatiales) in Guyancourt, France, within the planetary atmospheres and lidar engineering groups.
The student will work closely with:
• CNES (French Space Agency),
• ESA,
• industrial partners such as Winlight Optics and Airbus,
• and the wider European Mars science community.
The project offers a rare opportunity to contribute directly to the development of a cutting-edge spaceborne Doppler lidar that may become the first instrument to systematically measure winds on another planet.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Use of lasers