M/F Research contract on polychromatic wavefront sensing and control

Job Description

Missions

Over the past three decades, the discovery of nearly 6000 exoplanets has revealed an extraordinary diversity in planetary systems. Direct imaging —particularly coronagraphy—has emerged as one of the most promising methods for detecting and characterizing exoplanets in the habitable zone (HZ) of their host star. Such an approach is envisioned in future large facilities, e.g., NASA's Habitable Worlds Observatory (HWO) in space and ESO's Extremely Large Telescope (ELT) with the Planetary Camera and Spectrograph (PCS) on the ground.
The AMINO project (co-PIs: J. Mazoyer and V. Chambouleyron) aims to address some of the challenges associated with direct imaging, particularly for observing exo-Earths with planet/star flux ratios down to 10-10. One of them is the precise control of the incoming light aberrations with deformable optics to maintain areas of high-contrast regions (dark holes) over long periods of time and over a large spectral bandwitdh, which is critical for spectroscopy of faint planets.
The AMINO project focuses on advancing Focal Plane Wavefront Sensing (FPWFS) techniques, to estimate aberrations and create or maintain dark-holes. Our team has pioneered some of these techniques and is currently involved in their integration in both space and ground-based technological demonstrators: Coronagraph Instrument (CGI) on NASA's Roman Space Telescope and SPHERE+ on ESO's Very Large Telescope (VLT). But the efficiency of these FPWFS drops quickly in large spectral broadband: current instruments must rely on slow, sequential measurements in several narrow bands, which limit their performance.
The proposed work will look at two complementary methods for wavefront sensing and control: the Zernike wavefront sensor (ZWFS) and electric field conjugation with pairwise probing (EFC+PWP). These methods have been validated independently but have never been studied and used together to improve their respective performance. In this context, we work will be organised in two sequential parts:
1. Simulation and design of a polychromatic ZWFS: The selected applicant will conduct simulations to explore the parameter space of the THD2 testbed and find the optimal design for the Zernike mask. Then the mask will be designed, manufactured (by an external company) and verified on the LAM metrology platform. In parallel the postdoc will investigate in simulation how to best combine ZWFS measurements with EFC+PWP for dark hole digging and maintenance.
2. Implementation on the THD2 testbed at LIRA: The ZWFS component and methods explored in simulation will then be implemented on the THD2 testbed in Paris for broadband dark-hole digging and maintenance. The performance of the different methods or their combination will be investigated and compared in the context for future space missions.
In addition to these two main parts, the selected applicant may have the opportunity to participate in data acquisition at the VLT with the SPHERE/IFS instrument, where ZWFS and EFC+PWP are available. This part of the project will be subject to acceptance of technical time on SPHERE, which cannot be guaranteed now.

Activity

The following activities are expected to be carried out during the contract:
• Data simulation (in Python)
• Optical bench design
• Optical bench alignment
• Data acquisition, analysis and interpretation

Your Profil

Skills

• Wavefront sensing and control
• Fourier optics
• Numerical data analysis
• Python programming with main scientific libraries
• Fluency in written and spoken English
• Team work

Your Work Environment

We value diversity of backgrounds and perspectives as essential drivers for innovation and collective success. We are committed to fostering an inclusive environment where everyone feels valued and supported in their professional development.
The researcher will work between LAM and LIRA, which both have a wide range of expertise in instrumentation and astrophysical exploitation. The selected candidate will also be a member of the broader AMINO project that gathers experts in the field of brown dwarfs and exoplanets, adaptive optics, coronagraphy, wavefront sensors, and detectors at LIRA (Paris), LUX (Paris), LAM (Marseille) and Lagrange (Nice). Additional collaborations include the Makidon Lab at the Space Telescope Science Institute (Baltimore, USA) for space applications towards HWO.
The selected candidate will benefit from a rich national and international scientific environment and will have the opportunity to share their work with the community through international schools and conferences.

Contract duration: 12 months + 12-month extension

Constraints and risks

Ideally, the selected candidate will spend one year in Marseille and one year in Paris, but this is flexible given the complexity of the logistics involved. Instead of a complete move from one place to the other, long-duration stays could be considered provided that dedicated funding can be secured.

Compensation and benefits

Compensation

€3,131.32 to €4,806.76 gross/month, depending on experience.

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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