Study of an achromatic phase shifter "chessboards" in a nulling interferometer for the future characterization of exoplanets.

Direct detection of exoplanets is mandatory in order to characterize them. However, this is a hard task because of the small angular separation and high contrast between the host star and the planet. Nulling interferometry is one possible way, but it require an achromatic phase shifter. In this thesis a new phase shifter is studied, "the chessboards ". It is two mirrors or glass plate made of several cells, which position and phase shift are constrained by a mathematical scheme. The main effect is that for a given attenuation, the spectral bandwidth spreads as the number of cells in the chessboards increases, which gives the chessboards a quasi achromatic behavior. An automated test bench has been built in order to measure the attenuation produced by the chessboards in the visible. The first results have been obtained with chessboards made by photolithography on a glass plate, and an attenuation of 500 has been measured with a white laser beam. The cells' phase shift errors are the major source of loss of performance. Those generated by the fabrication process being irreversible, one chose to work with a segmented mirror that allows us to control the phase shift of each cells. In order synthesize the chessboards, the control of each cells' phase shift is mandatory and achieved by strioscopy. Thus, one can measure the chessboards behavior with respect to the wavelength, and experimentally validate the quasi-achromatic behavior of the chessboards.

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Source https://theses.hal.science/tel-00837512
Author Pickel, Damien
Maintainer CCSD
Last Updated May 10, 2026, 14:37 (UTC)
Created May 10, 2026, 14:37 (UTC)
Identifier tel-00837512
Language fr
Rights https://about.hal.science/hal-authorisation-v1/
contributor Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
creator Pickel, Damien
date 2012-11-20T00:00:00
harvest_object_id 8be6dfc8-3df9-4181-a8a6-e90a2ff53b3c
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-08-12T00:00:00
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