Focal Plane Wavefront Sensing using Residual Adaptive Optics Speckles

Abstract

Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate for these flaws, either to enhance Strehl ratio or suppress residual coronagraphic halo. Measurement of the phase and amplitude of the starlight halo at the science camera is essential for determining the DM shape that compensates for any non-common-path (NCP) wavefront errors. Using DM displacement ripples to create a series of probe and anti-halo speckles in the focal plane has been proposed for space-based coronagraphs and successfully demonstrated in the lab. We present the theory and first on-sky demonstration of a technique to measure the complex halo using the rapidly-changing residual atmospheric speckles at the 6.5m MMT telescope using the Clio mid-IR camera. The AO system's wavefront sensor (WFS) measurements are used to estimate the residual wavefront, allowing us to approximately compute the rapidly-evolving phase and amplitude of speckle halo. When combined with relatively-short, synchronized science camera images, the complex speckle estimates can be used to interferometrically analyze the images, leading to an estimate of the static diffraction halo with NCP effects included. In an operational system, this information could be collected continuously and used to iteratively correct quasi-static NCP errors or suppress imperfect coronagraphic halos.

Astrophysical Journal (accepted). 26 pages, 21 figures

References in corpus (6)

• Temporal Evolution of Coronagraphic Dynamic Range, and Constraints on Companions to Vega
• Astrometry and Photometry with Coronagraphs
• First On-Sky High Contrast Imaging with an Apodizing Phase Plate
• The First Direct Distance and Luminosity Determination for a Self-Luminous Giant Exoplanet: The Trigonometric Parallax to 2MASS1207334-393254Ab
• Utilization of the Wavefront Sensor and Short-Exposure Images for Simultaneous Estimation of Quasi-static Aberration and Exoplanet Intensity
• Clio: a 3-5 micron AO planet-finding camera

Cited by in corpus (21)

• Instrumentation for the detection and characterization of exoplanets
• The Vector-APP: a Broadband Apodizing Phase Plate that yields Complementary PSFs
• The coronagraphic Modal Wavefront Sensor: a hybrid focal-plane sensor for the high-contrast imaging of circumstellar environments
• Imaging low-mass planets within the habitable zone of α Centauri
• Large Binocular Telescope Interferometer Adaptive Optics: On-sky performance and lessons learned
• Lyot-plane phase masks for improved high-contrast imaging with a vortex coronagraph
• Single conjugate adaptive optics for the ELT instrument METIS
• On-sky validation of image-based adaptive optics wavefront sensor referencing
• Millisecond Exoplanet Imaging, I: Method and Simulation Results
• High-Contrast Coronagraphy
• Review of high-contrast imaging systems for current and future ground-based and space-based telescopes II. Common path wavefront sensing/control and Coherent Differential Imaging
• High contrast imaging for the enhanced resolution imager and spectrometer (ERIS)
• The polarization-encoded self-coherent camera
• Simultaneous ultra-high contrast imaging and determination of time-dependent, non-common path aberrations in the presence of detector noise
• InnoPOL: an EMCCD imaging polarimeter and 85-element curvature AO system on the 3.6-m AEOS telescope for cost effective polarimetric speckle suppression
• A Statistical Framework for the Utilization of Simultaneous Pupil Plane and Focal Plane Telemetry for Exoplanet Imaging, Part I: Accounting for Aberrations in Multiple Planes
• Reduced Order Estimation of the Speckle Electric Field History for Space-Based Coronagraphs
• Impact of water vapor seeing on mid-infrared high-contrast imaging at ELT scale
• The Mysterious Lives Of Speckles. I. Residual atmospheric speckle lifetimes in ground-based coronagraphs
• Empirical Green's Function Approach for Utilizing Millisecond Focal and Pupil Plane Telemetry in Exoplanet Imaging
• Direct Imaging of Exoplanets Without Background Subtraction: Implications for ELTs