Detecting and characterizing exoplanets with multicolor detector assemblies

Detecting and characterizing exoplanets is one of the main science drives for extremely large telecopes. It requires a high-order (extreme) adaptive optics (ExAO) system combined with a coronagraph and a science camera optimized for efficient attenuation of point spread function (PSF) residuals induced by atmospheric speckles and high-frequency quasi-static aberrations. Spectral differential imaging is a very promising technique for attenuating PSF residuals. High-contrast imaging observations with the TRIDENT camera at the AO focus of the Canada-France-Hawaii Telescope (CFHT) have shown that companion detection using differential imaging is seriously compromised by very small amount of non-common path wave front errors between the different optical channels of the camera. Such problems can be eliminated with a new type of detector assembly: a multi-color detector assembly (MCDA). This paper describes the MCDA concept along with numerical simulations predicting the combined performance of an ExAO system with a Lyot coronagraph and an MCDA on a segmented 20m telescope.