WFIRST coronagraph: digging dark-holes with partially corrected pupil phase
Abstract
The WFIRST coronagraph employs two sequential deformable mirrors to compensate for phase and amplitude errors in the coronagraph optical system. In such a system the actuators of the deformable mirrors would be used for two purposes: To flatten the overall wavefront errors at a system pupil, and to create "dark-holes". The actuators have limited stroke ranges. Therefore, if the pupil phase errors are relatively large, flattening them completely could use up a significant portion of the actuator stroke, sometimes leaving insufficient stroke for creating the dark-holes. We have investigated the impact of partially-corrected pupil phase errors on a Hybrid Lyot Coronagraph (HLC) broadband contrast performance. The predicted broadband contrast floor agrees well with those measured on the HLC testbed.
- Publication:
-
Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave
- Pub Date:
- July 2018
- DOI:
- 10.1117/12.2313520
- Bibcode:
- 2018SPIE10698E..6WS