Laboratory comparison of coronagraphic concepts under dynamical seeing and high-order adaptive optics correction

This is the authors' abstract. We don't add key points for this paper.

The exoplanetary science through direct imaging and spectroscopy will largely expand with the forthcoming development of new instruments at the Very Large Telescope (VLT; SPHERE), Gemini (GPI), Subaru (HiCIAO) and Palomar (Project 1640) observatories. All these ground-based adaptive optics instruments combine extremely high performance adaptive optics systems correcting for the atmospheric turbulence with advanced starlight-cancellation techniques such as coronagraphy to deliver contrast ratios of about 10−6 to 10−7. While the past 15 yr have seen intensive research and the development of high-contrast coronagraph concepts, very few concepts have been tested under dynamical seeing conditions (either during sky observation or in a realistic laboratory environment). In this paper, we discuss the results obtained with four different coronagraphs – phase and amplitude types – on the High-Order Testbench, the adaptive optics facility developed at ESO. This facility emphasizes realistic conditions encountered at a telescope (e.g. VLT), including a turbulence generator and a high-order adaptive optics system. It enables to evaluate the performance of high-contrast coronagraphs in the near-infrared operating with an adaptive optics corrected point spread function of 90 per cent Strehl ratio under 0.5 arcsec dynamical seeing.