Comparison of coronagraphs for high contrast imaging in the context of Extremely Large Telescopes

Abstract

We compare coronagraph concepts and investigate their behavior and suitability for planet finder projects with Extremely Large Telescopes (ELTs, 30-42 meters class telescopes). For this task, we analyze the impact of major error sources that occur in a coronagraphic telescope (central obscuration, secondary support, low-order segment aberrations, segment reflectivity variations, pointing errors) for phase, amplitude and interferometric type coronagraphs. This analysis is performed at two different levels of the detection process: under residual phase left uncorrected by an eXtreme Adaptive Optics system (XAO) for a large range of Strehl ratio and after a general and simple model of speckle calibration, assuming common phase aberrations between the XAO and the coronagraph (static phase aberrations of the instrument) and non-common phase aberrations downstream of the coronagraph (differential aberrations provided by the calibration unit). We derive critical parameters that each concept will have to cope with by order of importance. We evidence three coronagraph categories as function of the accessible angular separation and proposed optimal one in each case. Most of the time amplitude concepts appear more favorable and specifically, the Apodized Pupil Lyot Coronagraph gathers the adequate characteristics to be a baseline design for ELTs.

12 pages, 6 figures, Accepted for publication in A&A

References in corpus (13)

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Cited by in corpus (12)

• High Performance Lyot and PIAA Coronagraphy for Arbitrarily shaped Telescope Apertures
• High Contrast Imaging with an Arbitrary Aperture: Active Correction of Aperture Discontinuities
• Design, analysis and test of a microdots apodizer for the Apodized Pupil Lyot Coronagraph
• On-sky multi-wavelength phasing of segmented telescopes with the Zernike phase contrast sensor
• Improved achromatization of phase mask coronagraphs using colored apodization
• Design, analysis, and testing of a microdot apodizer for the Apodized Pupil Lyot Coronagraph. II. The dot size impact. (Research Note)
• Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging
• Band-Limited Coronagraphs using a Halftone-dot process: design guidelines, manufacturing, and laboratory results
• Shaped pupil design for the Gemini Planet Imager
• Laboratory comparison of coronagraphic concepts under dynamical seeing and high-order adaptive optics correction
• Apodized-pupil Lyot coronagraphs: multistage designs for extremely large telescopes
• Band-Limited Coronagraphs using a halftone-dot process: II. Advances and laboratory results for arbitrary telescope apertures