High dynamic range imaging by pupil single-mode filtering and remapping

Guy Perrin (1, 2) , Sylvestre Lacour (1, 2) , Julien M. Woillez (3) , Eric Thiébaut (4)

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 Pôle Astronomie du LESIA
3 W. M. Keck Observatory
4 CRAL - Centre de Recherche Astrophysique de Lyon

Because of atmospheric turbulence, obtaining high angular resolution images with a high dynamic range is difficult even in the near-infrared domain of wavelengths. We propose a novel technique to overcome this issue. The fundamental idea is to apply techniques developed for long baseline interferometry to the case of a single-aperture telescope. The pupil of the telescope is broken down into coherent subapertures each feeding a single-mode fibre. A remapping of the exit pupil allows interfering all subapertures non-redundantly. A diffraction-limited image with very high dynamic range is reconstructed from the fringe pattern analysis with aperture synthesis techniques, free of speckle noise. The performances of the technique are demonstrated with simulations in the visible range with an 8-m telescope. Raw dynamic ranges of 1:10⁶ can be obtained in only a few tens of seconds of integration time for bright objects.

Domains: Astrophysics [astro-ph]

Guy Perrin, Sylvestre Lacour, Julien M. Woillez, Eric Thiébaut. High dynamic range imaging by pupil single-mode filtering and remapping. Monthly Notices of the Royal Astronomical Society, 2006, 373, pp.747-751. ⟨10.1111/j.1365-2966.2006.11063.x⟩. ⟨hal-03797223⟩