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Etude et développement d'un déphaseur achromatique pour l'interférométrie en frange noire

Abstract : The Darwin mission is a project of the European Space Agency that should allow around 2015 the search for extrasolar planets and a spectral analysis of their atmospheres to detect gases and particularly tracers of life. The basic concept of the instrument is a Bracewell nulling interferometer. It allows the high angular resolution and high dynamic range necessary to cancel the light coming from the star to keep the planetary one.

The Darwin mission technological keypoints require preliminary laboratory experiments to validate each element before any space application. Among these, the Pi achromatic phase shifter included in the interferometer to cancel the starlight has to be achromatic in the whole Darwin spectral band from 6 to 18 microns. There are many solutions to create this phase shift. This work presents the study and development of one of these techniques based on dispersive prisms and tested on the polychromatic test bench SYNAPSE.

After an introduction of Darwin stakes, both from an exoplanetological and exobiological point of view, we introduce different achromatic phase shifter techniques. The concept based on prismatic dispersive plates is then detailed, along with the development of the SYNAPSE test bench working in near infrared. We finally show that this bench allowed to maintain rejection ratio better than 4 000 (corresponding to a 2,5.10-4 stellar leaks level) in the whole K band (from 2 to 2,5 microns) during several minutes. These results also show that more than the absolute rejection ratio needed in the whole Darwin spectral band, their stability will be the real stake during observations.
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Contributor : Frank Brachet <>
Submitted on : Monday, March 20, 2006 - 5:52:34 PM
Last modification on : Friday, October 23, 2020 - 4:54:45 PM
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  • HAL Id : tel-00011990, version 1



Frank Brachet. Etude et développement d'un déphaseur achromatique pour l'interférométrie en frange noire. Astrophysique [astro-ph]. Université Paris Sud - Paris XI, 2005. Français. ⟨tel-00011990⟩



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