The achromatic phase knife coronagraph
Observatoire de la Côte d'Azur, Département Fresnel, CNRS UMR 6528, 06460 Saint Vallier de Thiey, France
2 Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
Corresponding author: L. Abe, Lyu.Abe@obs-azur.fr
Accepted: 11 April 2001
We present the concept of a nulling coronagraph which theoretically attains the brightness ratio of 108 suitable to directly detect exo-Earths in the vicinity of their parent stars. The concept is derived from the classical Foucault's optics test and Zernike's self-destructive phase contrast principle. We propose an achromatic set-up which should dramatically improve its wide band efficiency. The whole system is simulated against a numerical model which validates a formal analytical approach. The coronagraph is then compared to other concepts and its advantages and shortcomings are outlined, suggesting future laboratory developments and tests on the sky.
Key words: techniques: interferometric / stars: binaries: close / stars: planetary systems
© ESO, 2001