Wavefront sensing and control in space-based coronagraph instruments using Zernike's phase-contrast method

Abstract

Future space telescopes with coronagraph instruments will use a wavefront sensor (WFS) to measure and correct for phase errors and stabilize the stellar intensity in high-contrast images. The HabEx and LUVOIR mission concepts baseline a Zernike wavefront sensor (ZWFS), which uses Zernike's phase contrast method to convert phase in the pupil into intensity at the WFS detector. In preparation for these potential future missions, we experimentally demonstrate a ZWFS in a coronagraph instrument on the Decadal Survey Testbed in the High Contrast Imaging Testbed facility at NASA's Jet Propulsion Laboratory. We validate that the ZWFS can measure low- and mid-spatial frequency aberrations up to the control limit of the deformable mirror, with surface height sensitivity as small as 1 pm, using a configuration similar to the HabEx and LUVOIR concepts. Furthermore, we demonstrate closed-loop control, resolving an individual DM actuator, with residuals consistent with theoretical models. In addition, we predict the expected performance of a ZWFS on future space telescopes using natural starlight from a variety of spectral types. The most challenging scenarios require ~1 hr of integration time to achieve picometer sensitivity. This timescale may be drastically reduced by using internal or external laser sources for sensing purposes. The experimental results and theoretical predictions presented here advance the WFS technology in the context of the next generation of space telescopes with coronagraph instruments.

Accepted for publication in JATIS

References in corpus (15)

• Habitable Zones Around Main-Sequence Stars: New Estimates
• Limits of Adaptive Optics for high contrast imaging
• Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor
• Optimal Dark Hole Generation via Two Deformable Mirrors with Stroke Minimization
• Speckle noise and dynamic range in coronagraphic images
• Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor. II. Concept validation with ZELDA on VLT/SPHERE
• Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor. III. On-sky validation in VLT/SPHERE
• Vortex coronagraphs for the Habitable Exoplanet Imaging Mission (HabEx) concept: theoretical performance and telescope requirements
• On-sky multi-wavelength phasing of segmented telescopes with the Zernike phase contrast sensor
• General formalism for Fourier based Wave Front Sensing
• Fine cophasing of segmented aperture telescopes with ZELDA, a Zernike wavefront sensor in the diffraction-limited regime
• Simultaneous phase and amplitude aberration sensing with a liquid-crystal vector-Zernike phase mask
• Increasing the raw contrast of VLT/SPHERE with the dark hole technique. I. Simulations and validation on the internal source
• Review of high-contrast imaging systems for current and future ground- and space-based telescopes I. Coronagraph design methods and optical performance metrics
• Laser Guide Star for Large Segmented-Aperture Space Telescopes, Part I: Implications for Terrestrial Exoplanet Detection and Observatory Stability

Cited by in corpus (12)

• End-to-end numerical modeling of the Roman Space Telescope coronagraph
• Flight mask designs of the Roman Space Telescope Coronagraph Instrument
• Modeling noise propagation in Fourier-filtering wavefront sensing, fundamental limits and quantitative comparison
• Calibration of residual aberrations in exoplanet imagers with large numbers of degrees of freedom
• The polarization-encoded self-coherent camera
• Adaptive optics performance of a simulated coronagraph instrument on a large, segmented space telescope in steady state
• Flight masks of the Roman Space Telescope Coronagraph Instrument
• Cascade adaptive optics with a second stage based on a Zernike wavefront sensor for exoplanet observations
• Dual Purpose Lyot Coronagraph Masks for Simultaneous High-Contrast Imaging and High-Resolution Wavefront Sensing
• On-sky reconstruction of Keck Primary Mirror Piston Offsets using a Zernike Wavefront Sensor
• Low-order wavefront control using a Zernike sensor through Lyot coronagraphs for exoplanet imaging
• Mid-order wavefront control for exoplanet imaging: preliminary characterization of the segmented deformable mirror and Zernike wavefront sensor on HiCAT