Achromatic dual-zone phase mask stellar coronagraph
Laboratoire Universitaire d'Astrophysique de Nice – UMR 6525, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France e-mail: Claude.Aime@unice.fr
2 Laboratoire d'Astrophysique de Marseille, 2 place Leverrier, 13248 Marseille, Cedex 4, France e-mail: Kjetil.Dohlen@oamp.fr
Corresponding author: R. Soummer, Remi.Soummer@unice.fr
Accepted: 14 February 2003
This paper presents a generalization of the Roddier & Roddier Phase Mask coronagraph for polychromatic observations. It is shown that using a dual-zone phase mask, combined with complex apodization, both phase and size chromatism can be compensated simultaneously to produce high extinction of a point source over large bandwidths, for example the entire K band with a residual integrated starlight of and a star intensity level of 10-6 at an angular separation of . Other advantages of the proposed technique include the compatibility with centrally obscured telescopes, absence of blind axes and no symmetrization of the images.
Key words: instrumentation: high angular resolution / techniques: high angular resolution / stars: planetary systems
© ESO, 2003