Phasing the Giant Magellan Telescope with the holographic dispersed fringe sensor

Haffert, Sebastiaan Y.; Close, Laird M.; Hedglen, Alexander D.; Males, Jared R.; Kautz, Maggie; Bouchez, Antonin H.; Demers, Richard; Quirós-Pacheco, Fernando; Sitarski, Breann N.; Gorkom, Kyle Van; Long, Joseph D.; Guyon, Olivier; Schatz, Lauren; Miller, Kelsey; Lumbres, Jennifer; Rodack, Alexander; Knight, J. H.

doi:10.1117/1.jatis.8.2.021513

Cited by 19 publications

(10 citation statements)

References 31 publications

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“…Therefore, we include the Holographic dispersed fringe sensor (HDFS) as a piston sensor for the GMT. 13 This sensor has been demonstrated to reach ¡30 nm piston rms for the GMT in a lab environment. 13,14 We assume that the HDFS is tracking and controlling the differential piston for the simulations in this work.…”

Section: Overview Of the Architecturementioning

confidence: 98%

Visible extreme adaptive optics for GMagAO-X with the triple-stage AO architecture (TSAO)

Haffert¹,

Males²,

Close³

et al. 2022

Preprint

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The Extremely Large Telescopes will require hundreds of actuators across the pupil for high Strehl in the visible. We envision a triple-stage AO (TSAO) system for GMT/GMagAO-X to achieve this. The first stage is a 4K DM controlled by an IR pyramid wavefront sensor that provides the first order correction. The second stage contains the high-order parallel DM of GMagAO-X that has 21000 actuators and contains an interferometric delay line for phasing of each mirror segment. This stage uses a Zernike wavefront sensor for high-order modes and a Holographic Dispersed Fringe Sensor for segment piston control. Finally, the third stage uses a dedicated 3K dm for non-common path aberration control and the coronagraphic wavefront control by using focal plane wavefront sensing and control. The triple stage architecture has been chosen to create simpler decoupled control loops. This work describes the performance of the proposed triple-stage AO architecture for ExAO with GMagAO-X.

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Section: Overview Of the Architecturementioning

confidence: 98%

Visible extreme adaptive optics for GMagAO-X with the triple-stage AO architecture (TSAO)

Haffert¹,

Males²,

Close³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The Holographic Dispersed Fringe Sensor (HDFS) is a new sensor that has been developped to measure differential piston on the GMT. 27 This sensor uses a hologram to combine pairs of segments of the GMT and it creates a dispersed fringe for each of the pairs. The piston can then be extracted from these dispersed fringes.…”

Section: Controlling Piston With Magao-xmentioning

confidence: 99%

“…28 The HDFS was tested both in simulation and in the lab with MagAO-X where we reached less than 50 nm rms on the piston modes. 27,29 It is now the 2nd stage wavefront sensor for the GMT facility AO system. 30…”

Section: Controlling Piston With Magao-xmentioning

confidence: 99%

Advanced wavefront sensing and control demonstration with MagAO-X

Haffert¹,

Males²,

Gorkom³

et al. 2022

Preprint

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The search for exoplanets is pushing adaptive optics systems on ground-based telescopes to their limits. Currently, we are limited by two sources of noise: the temporal control error and non-common path aberrations. First, the temporal control error of the AO system leads to a strong residual halo. This halo can be reduced by applying predictive control. We will show and described the performance of predictive control with the 2K BMC DM in MagAO-X. After reducing the temporal control error, we can target non-common path wavefront aberrations. During the past year, we have developed a new model-free focal-plane wavefront control technique that can reach deep contrast (<1e-7 at 5 λ/D) on MagAO-X. We will describe the performance and discuss the on-sky implementation details and how this will push MagAO-X towards imaging planets in reflected light. The new data-driven predictive controller and the focal plane wavefront controller will be tested on-sky in April 2022.

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“…The optical and mechanical design of GMagAO-X is presented in detail in these proceedings, 9 as are the details of our wavefront sensing strategy, 10 and the plans for segment phasing control 11 and the 21,000 actuator "parallel DM". 12 In brief, the main components of GMagAO-X consist of • Woofer DM: ALPAO DM 3228 (64 actuator diameter) 9 • 1st Stage WFS: 64x64 infrared Pyramid WFS 10 • Phase Control: 7x piezo T/T and Piston stages 9,11 • Tweeter DM: seven 3000 actuator MEMS DMs 9,12 • Coarse Phase Sensing: Holographic Dispersed Fringe Sensor 13,14 (HDFS, probably IR using 10% of J-H) GMagAO-X is designed to be build-able today, with existing technology. All of the above components can be purchased or fabricated today, making this instrument well suited to the early-science phase at GMT.…”

Section: Instrument Overview 31 Optical and Mechanical Designmentioning

confidence: 99%

The conceptual design of GMagAO-X: visible wavelength high contrast imaging with GMT

Males¹,

Close²,

Haffert³

et al. 2022

Preprint

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We present the conceptual design of GMagAO-X, an extreme adaptive optics system for the 25 m Giant Magellan Telescope (GMT). We are developing GMagAO-X to be available at or shortly after first-light of the GMT, to enable early high contrast exoplanet science in response to the Astro2020 recommendations. A key science goal is the characterization of nearby potentially habitable terrestrial worlds. GMagAO-Xis a woofer-tweeter system, with integrated segment phasing control. The tweeter is a 21,000 actuator segmented deformable mirror, composed of seven 3000 actuator segments. A multi-stage wavefront sensing system provides for bootstrapping, phasing, and high order sensing. The entire instrument is mounted in a rotator to provide gravity invariance. After the main AO system, visible (g to y) and near-IR (Y to H) science channels contain integrated coronagraphic wavefront control systems. The fully corrected and, optionally, coronagraphically filtered beams will then be fed to a suite of focal plane instrumentation including imagers and spectrographs. This will include existing facility instruments at GMT via fiber feeds. To assess the design we have developed an end-to-end frequencydomain modeling framework for assessing the performance of GMagAO-X. The dynamics of the many closed-loop feedback control systems are then modeled. Finally, we employ a frequency-domain model of post-processing algorithms to analyze the final post-processed sensitivity. The CoDR for GMagAO-X was held in September, 2021. Here we present an overview of the science cases, instrument design, expected performance, and concept of operations for GMagAO-X.

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Phasing the Giant Magellan Telescope with the holographic dispersed fringe sensor

Cited by 19 publications

References 31 publications

Visible extreme adaptive optics for GMagAO-X with the triple-stage AO architecture (TSAO)

Visible extreme adaptive optics for GMagAO-X with the triple-stage AO architecture (TSAO)

Advanced wavefront sensing and control demonstration with MagAO-X

The conceptual design of GMagAO-X: visible wavelength high contrast imaging with GMT

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