Simon ANS will defend his thesis entiled “Design of nanostructured blazed gratings for next-generation spectro-imagers“ on Friday, December 12, 2025 at 02:00 p.m., in Rouard amphitheater, campus St Jérôme, Marseille.
Members of jury :
- Anne-Sophie BONNET-BEN DHIA, UMA – ENSTA, Rapporteure
- Olivier J. F. MARTIN, NAM – EPFL, Rapporteur
- Amélie LITMAN, Institut Fresnel – Aix Marseille Université, Présidente du Jury
- Christophe GEUZAINE, EECS – Université de Liège, Examinateur
- Kevin VYNCK, ILM – CNRS, Examinateur
- Frédéric ZAMKOTSIAN, LAM – CNRS, Directeur de thèse
- Guillaume DEMESY, Institut Fresnel – Aix Marseille Université, Co-directeur de thèse
- Matthieu CASTELNAU, CNES, membre invité
- Hervé BENARD, Thales Alenia Space, membre invité
Abstract : Spectroscopy in the UV / Visible / Infrared ranges is a fundamental tool for Earth and Universe Observation. By separating the wavelengths that compose an electromagnetic field through light diffraction, it provides access to the chemical and/or atomic composition of observed objects and, in the case of very distant celestial bodies, their distance from Earth. The purpose of a blazed grating is to perform this wavelength separation with the highest throughput possible by favoring a particular diffraction order, thereby improving the signal-to-noise ratio of the observation. This thesis presents a design methodology for sub-wavelength (or metasurface) blazed gratings using topology optimization, outperforming current classical gratings in terms of effective spectral bandwidth. The study covers the near-UV (150 nm) to the near-infrared (2200 nm) with a particular focus on the [400–1500] nm range. This work is based on a deep physical and mathematical modeling of diffraction gratings to develop a powerful and versatile numerical optimization framework. A first blazed metasurface has been fabricated and serves as reference in terms of manufacturing capabilities.
