PhD Position: Coherent Differential Imaging

About the Project

Direct imaging of exoplanets is one of the most exciting and rapidly evolving areas of modern astronomy. By capturing light directly from exoplanets, astronomers can study planetary atmospheres, with the ultimate goal of detecting Earth-like planets and searching for biosignatures.

However, exoplanets are vastly fainter than their host stars. Coronagraphs help suppress starlight, enabling detection of faint planetary signals.

Next-generation telescopes such as the European Extremely Large Telescope (ELT) and NASA’s Habitable Worlds Observatory will rely on new high-contrast imaging techniques to detect habitable-zone planets.

This PhD is part of the ERC-funded ECHOES project (PI: Johan Mazoyer), aiming to develop cutting-edge coronagraphic and imaging techniques. The position is already fully funded.

Objectives of the PhD

The main objective is to develop and validate innovative post-processing techniques for detecting exoplanets in coronagraphic images.

Unlike traditional methods using angular or spectral diversity, this project focuses on Coherent Differential Imaging (CDI), which exploits the coherence properties of light to distinguish planets from stellar noise.

Key Research Goals

1. Enhancing CDI with Machine Learning

   • Use convolutional neural networks (CNNs) trained on simulations.

   • Improve speed and robustness of planet detection.

2. Developing New CDI Techniques

   • Explore new modulation-based CDI approaches.

   • Adapt CDI for single-frame, model-free post-processing methods.

Methods

The PhD will combine simulations, experimental validation, and observations:

1. Image Processing & Algorithm Development

• Develop coronagraphic simulation tools in Python.

• Design innovative CDI algorithms.

2. Experimental Validation

• Test algorithms on the THD2 optical testbed under realistic conditions.

3. On-Sky Observations

• Participate in observing runs at the Very Large Telescope using instruments like SPHERE instrument.

Outputs

Research results will be published in journals such as:

• Astronomy & Astrophysics

• Optics Express

• Journal of Astronomical Telescopes, Instruments, and Systems

and presented at conferences including:

• SPIE

• AO4ELT

Candidate Profile

Applicants should have:

• Master’s degree in:

  • Physics / Astrophysics

  • Optics

  • Computer Science

• Interest in instrumentation, signal processing, or experimental work

• Strong programming skills (Python required)

• Fluency in English (written and spoken)

Applicants without prior astrophysics experience are welcome.

Why Join Us?

You will join a leading exoplanet imaging group at Paris Observatory involved in major international projects, including:

• James Webb Space Telescope coronagraph instruments

• Roman Space Telescope Coronagraph Instrument

• MICADO

Collaborations include:

• European Southern Observatory

• NASA

• ONERA

This interdisciplinary PhD combines astrophysics, optics, and machine learning, offering strong career opportunities in academia, space agencies, and advanced technology industries.

Benefits

• Salary: ~€2,135 gross/month for 3 years

• Optional teaching assistant work (up to 64 hours/year with additional pay)

• Full social security coverage

• 75% reimbursement of public transportation costs

How to Apply

Send your application before March 30, 2026 (23:59 CET).

Subject line:
“ECHOES: Coherent differential imaging”

Include:

• CV / Resume

• Transcripts (last 2 academic years)

• One letter of recommendation