Optical and mechanical design of the extreme AO coronagraphic instrument MagAO-X

Close, Laird M.; Males, Jared R.; Durney, Olivier; Sauve, Corwynn; Kautz, Maggie; Hedglen, Alexander D.; Schatz, Lauren; Lumbres, Jennifer; Miller, Kelsey; Gorkom, Kyle Van; Jean, Madison; Gasho, Victor

doi:10.1117/12.2312280

Cited by 13 publications

(3 citation statements)

References 29 publications

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“…Only a handful of extreme Adaptive Optics (ExAO) instruments currently operate at visible wavelengths: VLT/SPHERE, 4 SUBARU/SCExAO 5 and Magellan/MagAO-X. 6,7 These facilities report raw contrasts on the order of ∼ 10 −3 at 100 mas, see Table 1. The leading limitation in all systems are non common path aberrations (NCPA) which can be both static and quasi-static.…”

Section: State Of Visible High-contrast Imaging From the Groundmentioning

confidence: 99%

Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Fowler,

Haffert,

van Kooten

et al. 2023

Techniques and Instrumentation for Detection of Exoplanets XI

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Looking to the future of exo-Earth imaging from the ground, core technology developments are required in visible extreme adaptive optics (ExAO) to enable the observation of atmospheric features such as oxygen on rocky planets in visible light. UNDERGROUND (Ultra-fast AO techNology Determination for Exoplanet imageRs from the GROUND), a collaboration built in Feb. 2023 at the Optimal Exoplanet Imagers Lorentz Workshop, aims to (1) motivate oxygen detection in Proxima Centauri b and analogs as an informative science case for high-contrast imaging and direct spectroscopy, (2) overview the state of the field with respect to visible exoplanet imagers, and (3) set the instrumental requirements to achieve this goal and identify what key technologies require further development.

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Section: State Of Visible High-contrast Imaging From the Groundmentioning

confidence: 99%

Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Fowler,

Haffert,

van Kooten

et al. 2023

Techniques and Instrumentation for Detection of Exoplanets XI

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“…MagAO-X uses a woofer-tweeter architecture with an ALPAO-97 DM as woofer and a Boston Micromachines 2K tweeter. 14,44 The system accepts an f∕11 beam that first hits the woofer and then the tweeter. This beam is relayed to the lower bench where the pyramid wavefront sensor (PWFS) and the science cameras sit.…”

Section: Setup Descriptionmentioning

confidence: 99%

Data-driven subspace predictive control of adaptive optics for high-contrast imaging

Haffert

Males

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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The search for exoplanets is pushing adaptive optics (AO) systems on ground-based telescopes to their limits. One of the major limitations at small angular separations, exactly where exoplanets are predicted to be, is the servo-lag of the AO systems. The servo-lag error can be reduced with predictive control where the control is based on the future state of the atmospheric disturbance. We propose to use a linear data-driven integral predictive controller based on subspace methods that are updated in real time. The new controller only uses the measured wavefront errors and the changes in the deformable mirror commands, which allows for closed-loop operation without requiring pseudo-open loop reconstruction. This enables operation with non-linear wavefront sensors such as the pyramid wavefront sensor. We show that the proposed controller performs nearoptimal control in simulations for both stationary and non-stationary disturbances and that we are able to gain several orders of magnitude in raw contrast. The algorithm has been demonstrated in the lab with MagAO-X, where we gain more than two orders of magnitude in contrast.

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“…The rest of the image, including the hMWFS and the bright field opposite the dark holes, will be reflected back to a second EMCCD, which will operate as the designated focal plane wavefront sensor. 19 Journal of Astronomical Telescopes, Instruments, and Systems 049004-17…”

Section: Ldfc Laboratory Demonstrationmentioning

confidence: 99%

Spatial linear dark field control and holographic modal wavefront sensing with a vAPP coronagraph on MagAO-X

Miller

Males

Guyon

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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The Magellan Extreme Adaptive Optics (MagAO-X) Instrument is an extreme AO system coming online at the end of 2019 that will be operating within the visible and near-IR. With state-of-the-art wavefront sensing and coronagraphy, MagAO-X will be optimized for high-contrast direct exoplanet imaging at challenging visible wavelengths, particularly Hα. To enable high-contrast imaging, the instrument hosts a vector apodizing phase plate (vAPP) coronagraph. The vAPP creates a static region of high contrast next to the star that is referred to as a dark hole; on MagAO-X, the expected dark hole raw contrast is ∼4 × 10 −6. The ability to maintain this contrast during observations, however, is limited by the presence of non-common path aberrations (NCPA) and the resulting quasi-static speckles that remain unsensed and uncorrected by the primary AO system. These quasi-static speckles within the dark hole degrade the high contrast achieved by the vAPP and dominate the light from an exoplanet. The aim of our efforts here is to demonstrate two focal plane wavefront sensing (FPWFS) techniques for sensing NCPA and suppressing quasi-static speckles in the final focal plane. To sense NCPA to which the primary AO system is blind, the science image is used as a secondary wavefront sensor. With the vAPP, a static high-contrast dark hole is created on one side of the PSF, leaving the opposite side of the PSF unocculted. In this unobscured region, referred to as the bright field, the relationship between modulations in intensity and low-amplitude pupil plane phase aberrations can be approximated as linear. The bright field can therefore be used as a linear wavefront sensor to detect small NCPA and suppress quasi-static speckles. This technique, known as spatial linear dark field control (LDFC), can monitor the bright field for aberrations that will degrade the high-contrast dark hole. A second form of FPWFS, known as holographic modal wavefront sensing (hMWFS), is also employed with the vAPP. This technique uses hologram-generated PSFs in the science image to monitor the presence of low-order aberrations. With LDFC and the hMWFS, high contrast across the dark hole can be maintained over long observations, thereby allowing planet light to remain visible above the stellar noise over the course of observations on MagAO-X. Here, we present simulations and laboratory demonstrations of both spatial LDFC and the hMWFS with a vAPP coronagraph at the University of Arizona Extreme Wavefront Control Laboratory. We show both in simulation and in the lab that the hMWFS can be used to sense low-order aberrations and reduce the wavefront error (WFE) by a factor of 3 − 4×. We also show in simulation that, in the presence of a temporally evolving pupil plane phase aberration with 27-nm root-mean-square (RMS) WFE, LDFC can reduce the WFE to 18-nm RMS, resulting in factor of 6 to 10 gain in contrast that is kept stable over time. This performance is also verified in the lab, showing that LDFC is capable of returning the dark hole to the average contrast e...

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Optical and mechanical design of the extreme AO coronagraphic instrument MagAO-X

Cited by 13 publications

References 29 publications

Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Data-driven subspace predictive control of adaptive optics for high-contrast imaging

Spatial linear dark field control and holographic modal wavefront sensing with a vAPP coronagraph on MagAO-X

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