The Four‐Quadrant Phase‐Mask Coronagraph. I. Principle

• DOI: 10.1086/317707
• Publication Date: 2002-07-26T19:01:31Z
• Authors: D. Rouan; P. Riaud; A. Boccaletti; Y. Clénet; A. Labeyrie
• Keywords: Coronagraph; Achromatic lens

We describe a new type of coronagraph, based on the principle phase mask as proposed by Roddier and few years ago but using an original design found one us (D. R.), four‐quadrant binary (0, π) covering full field view at focal plane. The mutually destructive interferences coherent light from main source produce very efficient nulling. computed rejection rate this coronagraph appears to be high since, when perfectly aligned phase‐error free, it could in reduce total amount bright factor 108, corresponding gain 20 mag brightness location first Airy ring, relative peak. In real world is course reduced strong factor, nulling still performing quite well, provided that perturbation phase, for instance, due Earth's atmosphere, efficiently corrected adaptive optics. show simulations detection contrast 10 between star faint companion achievable excellent conditions, while 8 routinely feasible. This less sensitive atmospheric turbulence has larger dynamic range than other recently techniques: phase‐mask (by Roddier) or Achromatic Interfero‐Coronagraph Gay Rabbia). present results series simulations. compare those with theoretical performances devices. briefly analyze different limitations space ground‐based observations, well issue manufacturing device. also discuss several ways improve around object. conclude that, respect previous techniques, instrument equipped should have better performance even enable imaging extrasolar giant planets young stage, coupled additional cleaning techniques.