Characterizing deformable mirrors for the MagAO-X instrument

Gorkom, Kyle Van; Males, Jared R.; Close, Laird M.; Lumbres, Jennifer; Hedglen, Alexander D.; Long, Joseph D.; Haffert, Sebastiaan Y.; Guyon, Olivier; Kautz, Maggie; Schatz, Lauren; Miller, Kelsey; Rodack, Alexander; Knight, J. H.; Morzinski, Katie M.

doi:10.1117/1.jatis.7.3.039001

Cited by 9 publications

(4 citation statements)

References 22 publications

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“…The speckles are created by an out-of-pupil phase screen that has a -2 power-law distribution and a total power of λ/10 peak-to-valley. These amounts of NCPA are quite representative of modern xAO systems, SPHERE has 50 nm (Beuzit et al 2019) of residuals phase aberrations while MagAO-X has less than 30 nm (Van Gorkom et al 2021). The phase screen is placed out of the pupil plane to induce some amount of amplitude aberrations.…”

Section: Coronagraph Comparisonmentioning

confidence: 99%

Implicit electric field conjugation: Data-driven focal plane control

Haffert¹,

Males²,

Ahn³

et al. 2023

A&A

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Context. Direct imaging of Earth-like planets is one of the main science cases for the next generation of extremely large telescopes. This is very challenging due to the star-planet contrast that has to be overcome. Most current high-contrast imaging instruments are limited in sensitivity at small angular separations due to non-common path aberrations (NCPA). The NCPA leak through the coronagraph and create bright speckles that limit the on-sky contrast and therefore also the post-processed contrast. Aims. We aim to remove the NCPA by active focal plane wavefront control using a data-driven approach. Methods. We developed a new approach to dark hole creation and maintenance that does not require an instrument model. This new approach is called implicit Electric Field Conjugation (iEFC) and it can be empirically calibrated. This makes it robust for complex instruments where optical models might be difficult to realize. Numerical simulations have been used to explore the performance of iEFC for different coronagraphs. The method was validated on the internal source of the Magellan Adaptive Optics eXtreme (MagAO-X) instrument to demonstrate iEFC's performance on a real instrument. Results. Numerical experiments demonstrate that iEFC can achieve deep contrast below 10 −9 with several coronagraphs. The method is easily extended to broadband measurements and the simulations show that a bandwidth up to 40% can be handled without problems. Lab experiments with MagAO-X showed a contrast gain of a factor 10 in a broadband light and a factor 20 to 200 in narrowband light. A contrast of 5 • 10 −8 was achieved with the Phase Apodized Pupil Lyot Coronagraph at 7.5 λ/D. Conclusions. The new iEFC method has been demonstrated to work in numerical and lab experiments. It is a method that can be empirically calibrated and it can achieve deep contrast. This makes it a valuable approach for complex ground-based high-contrast imaging systems.

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Section: Coronagraph Comparisonmentioning

confidence: 99%

Implicit electric field conjugation: Data-driven focal plane control

Haffert¹,

Males²,

Ahn³

et al. 2023

A&A

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“…We employ a parametric phase retrieval algorithm adapted from Thurman et al 2009 12 and implemented on MagAO-X 13 but modified to replace the angular spectrum propagation to defocused planes with a pair of defocus probes on the DM. We calibrate the PR response matrix similar to the procedure described in Van Gorkom et al 2021 13 but employ a set of Hadamard probes on the DM to calibrate the system 14 in place of grid patterns. Actuators outside the beam footprint on the DM are removed from the calculated control matrix and commanded to the mean of nearest-neighbor actuators.…”

Section: Strehl Ratio Optimizationmentioning

confidence: 99%

The space coronagraph optical bench (SCoOB): 2. Wavefront sensing and control in a vacuum-compatible coronagraph testbed for spaceborne high-contrast imaging technology

Gorkom

Douglas²,

Ashcraft³

et al. 2022

Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave

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The 2020 Decadal Survey on Astronomy and Astrophysics endorsed space-based high contrast imaging for the detection and characterization of habitable exoplanets as a key priority for the upcoming decade. To advance the maturity of starlight suppression techniques in a space-like environment, we are developing the Space Coronagraph Optical Bench (SCoOB) at the University of Arizona, a new thermal vacuum (TVAC) testbed based on the Coronagraphic Debris Exoplanet Exploring Payload (CDEEP), a SmallSat mission concept for high contrast imaging of circumstellar disks in scattered light. When completed, the testbed will combine a vector vortex coronagraph (VVC) with a Kilo-C microelectromechanical systems (MEMS) deformable mirror from Boston Micromachines Corp (BMC) and a self-coherent camera (SCC) with a goal of raw contrast surpassing 10 −8 at visible wavelengths. In this proceedings, we report on our wavefront sensing and control efforts on this testbed in air, including the as-built performance of the optical system and the implementation of algorithms for focalplane wavefront control and digging dark holes (regions of high contrast in the focal plane) using electric field conjugation (EFC) and related algorithms.

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“…Due to the COVID-19 Pandemic, it underwent an extended period of laboratory testing and upgrades between December 2019 and April 2022. Notable examples of the work done during this time are the implementation of Focus Diversity Phase Retrieval (FDPR). 22 FDPR is now used at the telescope to flatten the DMs to maximize Strehl at the focal plane, and the AO is then calibrated around this point. This procedure significantly improves on-sky Strehl.…”

Section: Lab Testbedmentioning

confidence: 99%

MagAO-X: current status and plans for Phase II

Males¹,

Close²,

Haffert³

et al. 2022

Preprint

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We present a status update for MagAO-X, a 2000 actuator, 3.6 kHz adaptive optics and coronagraph system for the Magellan Clay 6.5 m telescope. MagAO-X is optimized for high contrast imaging at visible wavelengths. Our primary science goals are detection and characterization of Solar System-like exoplanets, ranging from very young, still-accreting planets detected at H-alpha, to older temperate planets which will be characterized using reflected starlight. First light was in Dec, 2019, but subsequent commissioning runs were canceled due to COVID-19. In the interim, MagAO-X has served as a lab testbed. Highlights include implementation of several focal plane and low-order wavefront sensing algorithms, development of a new predictive control algorithm, and the addition of an IFU module. MagAO-X also serves as the AO system for the Giant Magellan Telescope High Contrast Adaptive Optics Testbed. We will provide an overview of these projects, and report the results of our commissioning and science run in April, 2022. Finally, we will present the status of a comprehensive upgrade to MagAO-X to enable extreme-contrast characterization of exoplanets in reflected light. These upgrades include a new post-AO 1000-actuator deformable mirror inside the coronagraph, latest generation sCMOS detectors for wavefront sensing, optimized PIAACMC coronagraphs, and computing system upgrades. When these Phase II upgrades are complete we plan to conduct a survey of nearby exoplanets in reflected light.

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Characterizing deformable mirrors for the MagAO-X instrument

Cited by 9 publications

References 22 publications

Implicit electric field conjugation: Data-driven focal plane control

Implicit electric field conjugation: Data-driven focal plane control

The space coronagraph optical bench (SCoOB): 2. Wavefront sensing and control in a vacuum-compatible coronagraph testbed for spaceborne high-contrast imaging technology

MagAO-X: current status and plans for Phase II

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