Developing and Demonstrating Linear Dark Field Control for Exo-Earth Imaging with the Ames Coronagraph Experiment Testbed
Abstract
Imaging rocky planets in reflected light, a key focus of future NASA missions and ELTs, requires advanced wavefront control to maintain a deep, temporally correlated null of stellar halo at just several diffraction beam widths. We present the first laboratory tests of the Linear Dark Field Control (LDFC) method at contrasts and separations required to image exo-Earths around low-mass stars with future ground-based 30m class telescopes, using the Ames Coronagraph Experiment testbed. LDFC uses the response to perturbations in uncorrected, 'bright field' regions to maintain a dark hole without continuous DM probing. Our results show LDFC able to restore a dark hole whose contrast is degraded by up to a factor of 10 by perturbations and maintain this dark hole. We present preliminary results showing its efficacy under a range of DM perturbations, describe current limitations/challenges, and discuss future plans for testing LDFC at raw contrasts needed to image solar system-like planets (including Earths) around Sun-like stars.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23534205C