Suppressing stellar residual light on extremely large telescopes by aperture modulation

¹ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany.
² Physics Department, Technion - Israel Institute of Technology, Haifa 32000, Israel
³ Instituto de Astrofisica de Canarias, C/ Via Lactea, s/n, E38205 - La Laguna, Spain
⁴ Leiden Observatory, University of Leiden, Niels Bohrweg 2, NL-2333 CA Leiden, The Netherlands
⁵ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
⁶ Gemini Observatory, Hilo, Hawaii 96720, USA

^a e-mail: sgladysz@eso.org

Abstract

Efficient suppression of the residual stellar light is paramount to the success of exoplanet imaging efforts. We present a new approach to diffraction suppression on extremely large telescopes. The method is based on the realization that by obscuring part of the wavefront in the Lyot stop we can change the shape of the corresponding PSF. This obscuration is then modulated leading to modulated Airy pattern, while image of a planet - if present - is only slightly affected. The modulation could then be removed from the set of images, leading to better SNR of the possible planets. Simulation of the European Extremely Large Telescope has been used to test this approach.