Low order wavefront sensing and control for WFIRST-AFTA coronagraph

Balasubramanian, Kunjithapatham; Bartos, Randall; Hein, Randall C.; Kern, Brian; Krist, John; Lam, Raymond; Moore, Douglas M.; Moore, James D.; Patterson, Keith; Poberezhskiy, Ilya; Shields, Joel; Sidick, Erkin; Tang, Hong; Truong, Trieu‐Kien; Wallace, J. Kent; Wang, Xu; Wilson, Dan

doi:10.1117/12.2188775

Cited by 11 publications

(6 citation statements)

References 2 publications

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“…For WFIRST, a low-order wavefront sensing (LOWFS) system has been developed and demonstrated to sense and correct tip, tilt, and focus. 16 Further development will be required for ATLAST to include additional low-order wavefront terms, including coma, astigmatism, and spherical aberration, as well as maintain a higher level of correction of these terms to achieve the 10 pm RMS stability requirement. It is also worth noting that metrology systems discussed in Sec.…”

Section: Wavefront Sensing and Controlmentioning

confidence: 99%

Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

Bolcar

Balasubramanian

Crooke

et al. 2016

J. Astron. Telesc. Instrum. Syst

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The Advanced Technology Large Aperture Space Telescope (ATLAST) team identified five key technology areas to enable candidate architectures for a future large-aperture ultraviolet/optical/ infrared (LUVOIR) space observatory envisioned by the NASA Astrophysics 30-year roadmap, "Enduring Quests, Daring Visions." The science goals of ATLAST address a broad range of astrophysical questions from early galaxy and star formation to the processes that contributed to the formation of life on Earth, combining general astrophysics with direct-imaging and spectroscopy of habitable exoplanets. The key technology areas are internal coronagraphs, starshades (or external occulters), ultra-stable large-aperture telescope systems, detectors, and mirror coatings. For each technology area, we define best estimates of required capabilities, current state-of-the-art performance, and current technology readiness level (TRL), thus identifying the current technology gap. We also report on current, planned, or recommended efforts to develop each technology to TRL 5.

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Section: Wavefront Sensing and Controlmentioning

confidence: 99%

Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

Bolcar

Balasubramanian

Crooke

et al. 2016

J. Astron. Telesc. Instrum. Syst

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“…Laboratory demonstration of the concept have been carried out in this context. 25 We have also performed preliminary tests and obtained encouraging results of the Zernike sensor on the coronagraphic testbed in Marseille. [26][27][28] In 2014, we implemented a prototype called ZELDA (Zernike sensor for Extremely Low-level Differential Aberrations) in the SPHERE instrument at the VLT.…”

Section: Introductionmentioning

confidence: 89%

ZELDA, a Zernike sensor for accurate calibration of aberrations in coronagraphic instruments: validation in VLT/SPHERE and preliminary on-sky results

Vigan¹,

N’Diaye²,

Dohlen³

et al. 2017

Proceedings of the Adaptive Optics for Extremely Large Telescopes 5

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Gas giant planets, brown dwarfs, and debris disks around nearby stars are now routinely observed by dedicated high-contrast imaging instruments on large, ground-based observatories. These facilities combine extreme adaptive optics and coronagraphy to achieve unprecedented sensitivities for exoplanet detection and spectral characterization. However, residual quasi-static phase aberrations in these coronagraphic systems represent a critical limitation for the detection of giant planets with a contrast lower than a few 10 −6 at very small separations (<0.3) from their host star. In 2013 we proposed ZELDA, a Zernike wavefront sensor to measure these phase aberrations at a nanometric level. Relying on a prototype installed in VLT/SPHERE in 2014, we performed multiple tests in December 2015 and demonstrated the capability of our concept to accurately measure well-known aberrations on internal source. We also showed a contrast improvement by a factor of 10 at 0.2 for this instrument by calibrating its residual aberrations with our device. After a brief review of this experimental validation, we present preliminary on-sky results on SPHERE obtained in March 2017. This new data set relies on ZELDA estimate of quasi-static aberrations on the internal source. We finally discuss perspectives for future ELT instrumentation with ZELDA.

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“…To compensate, CGI will have a dedicated LOWFS/C system for Zernike modes 2-11. 7 The Zernike phase contrast wavefront sensor will use the starlight reflected by the coronagraph occulting masks and will operate during science observations. A fast steering mirror will correct tip/tilt jitter at frequencies 20 Hz; other modes will be corrected at 5 mHz with a combination of a dedicated focus corrector and deformable mirrors (DMs).…”

Section: Wavefront Sensing and Controlmentioning

confidence: 99%

Lessons for WFIRST CGI from ground-based high-contrast systems

Bailey

Bottom

Cady

et al. 2018

Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

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The Coronagraph Instrument (CGI) for NASA's Wide Field Infrared Survey Telescope (WFIRST) will constitute a dramatic step forward for high-contrast imaging, integral field spectroscopy, and polarimetry of exoplanets and circumstellar disks, aiming to improve upon the sensitivity of current ground-based direct imaging facilities by 2-3 orders of magnitude. Furthermore, CGI will serve as a pathfinder for future exo-Earth imaging and characterization missions by demonstrating wavefront control, coronagraphy, and spectral retrieval in a new contrast regime, and by validating instrument and telescope models at unprecedented levels of precision. To achieve this jump in performance, it is critical to draw on the experience of ground-based high-contrast facilities. We discuss several areas of relevant commonalities, including: wavefront control, post-processing of integral field unit data, and calibration and observing strategies.

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Low order wavefront sensing and control for WFIRST-AFTA coronagraph

Cited by 11 publications

References 2 publications

Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

ZELDA, a Zernike sensor for accurate calibration of aberrations in coronagraphic instruments: validation in VLT/SPHERE and preliminary on-sky results

Lessons for WFIRST CGI from ground-based high-contrast systems

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