The Santa Cruz Extreme AO Lab (SEAL): design and first light

Jensen-Clem, Rebecca; Dillon, Daren; Gerard, Benjamin L.; Kooten, Maaike A. M. van; Fowler, J.; Kupke, Renate; Cetre, Sylvain; Sanchez, Dominic; Hinz, Philip; Laguna, Cesar; Doelman, David; Snik, Frans

doi:10.1117/12.2594676

Cited by 7 publications

(9 citation statements)

References 8 publications

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“…Although we will refer to this setup as the Santa cruz Extreme AO Laboratory (SEAL), SEAL will ultimately be a mostly reflective setup designed for multipurpose AO-based wavefront sensing and control techniques, beyond the scope of just testing FAST; the higherlevel setup of the full SEAL testbed, including the optical design and both current and ongoing projects (including FAST), are presented and described in Ref. 16. Note that the main facilities used here are the same as previously described in Ref.…”

Section: Setupmentioning

confidence: 99%

“…13 In this paper, we will discuss related laboratory developments of one such technology, based on the self-coherent camera (SCC), 14 called the fast atmospheric SCC technique (FAST), 4,15 using the Santa Cruz Extreme AO Laboratory (SEAL). 16 This FAST concept was initially developed at the high contrast testbed at the National Research Council of Canada Herzberg Astronomy and Astrophysics research center, which has published a laboratory optical design and preliminary FAST testing results in Ref. 17.…”

Section: Introductionmentioning

confidence: 99%

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Laboratory demonstration of real-time focal plane wavefront control of residual atmospheric speckles

Gerard¹,

Dillon²,

Cetre³

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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Current and future high contrast imaging instruments aim to detect exoplanets at closer orbital separations, lower masses, and/or older ages than their predecessors. However, continually evolving speckles in the coronagraphic science image limit contrasts of state-ofthe-art ground-based exoplanet imaging instruments. For ground-based adaptive optics (AO) instruments, it remains challenging for most speckle suppression techniques to attenuate both the dynamic atmospheric as well as quasistatic instrumental speckles on-sky. We have proposed a focal plane wavefront sensing and control algorithm to address this challenge, called the fast atmospheric selfcoherent camera (SCC) technique (FAST), which in theory enables the SCC to operate down to millisecond timescales even when only a few photons are detected per speckle. Here, we present the first experimental results of FAST on the Santa Cruz Extreme AO Laboratory (SEAL) testbed. In particular, we illustrate the benefit of "second stage" AO-based focal plane wavefront control, demonstrating up to 5× contrast improvement with FAST closedloop compensation of evolving residual atmospheric turbulence-both for low and high order spatial modes-down to 20-ms timescales.

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Section: Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laboratory demonstration of real-time focal plane wavefront control of residual atmospheric speckles

Gerard¹,

Dillon²,

Cetre³

et al. 2022

J. Astron. Telesc. Instrum. Syst.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although we will refer to this setup as the Santa cruz Extreme AO Laboratory (SEAL), SEAL will ultimately be a mostly reflective setup designed for multi-purpose AO-based wavefront sensing and control techniques, beyond the scope of just testing FAST; the higher-level setup of the full SEAL testbed, including the optical design and both current and ongoing projects (including FAST), are presented and described in Ref. 16. Note that the main facilities used here are the same as previously described in Ref.…”

Section: Setupmentioning

confidence: 99%

“…Ref. 16 describes more specifically the hardware and infrastructure for SEAL software control and development, which includes a GPU-based clone of the Keck RTC in Linux (which we will refer to as the SEAL RTC) and a Windows machine for some off-the-shelf components without available Linux drivers. Low-level drivers for the MEMS and Andor camera (i.e., to get and send DM commands and to get images/sub-arrays) are written on the SEAL RTC in C and interfaced with Python to enable high-level FAST software development.…”

Section: Setupmentioning

confidence: 99%

Laboratory Demonstration of Real-Time Focal Plane Wavefront Control of Residual Atmospheric Speckles

Gerard¹,

Dillon²,

Cetre³

et al. 2022

Preprint

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Current and future high contrast imaging instruments aim to detect exoplanets at closer orbital separations, lower masses, and/or older ages than their predecessors. However, continually evolving speckles in the coronagraphic science image limit contrasts of state-of-the-art ground-based exoplanet imaging instruments. For ground-based adaptive optics (AO) instruments it remains challenging for most speckle suppression techniques to attenuate both the dynamic atmospheric as well as quasi-static instrumental speckles on-sky. We have proposed a focal plane wavefront sensing and control algorithm to address this challenge, called the Fast Atmospheric Self-coherent camera (SCC) Technique (FAST), which in theory enables the SCC to operate down to millisecond timescales even when only a few photons are detected per speckle. Here we present the first experimental results of FAST on the Santa Cruz Extreme AO Laboratory (SEAL) testbed. In particular, we illustrate the benefit of "second stage" AO-based focal plane wavefront control, demonstrating up to 5x contrast improvement with FAST closed-loop compensation of evolving residual atmospheric turbulence-both for low and high order spatial modes-down to 20 millisecond-timescales.

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“…Comparing EOF to other controllers is underway in a laboratory setting at University of California Santa Cruz on the SEAL test bench. 36 We will compare predictive control not only to other types of predictive controllers but also to other controllers such as modal gain control. In our own simulations and with telemetry data the EOF and the RLMMSE algorithms have the same performance when the appropriate regressors and training data are selected.…”

Section: Comparing Eof To Other Controllersmentioning

confidence: 99%

Predictive wavefront control on Keck II adaptive optics bench: on-sky coronagraphic results

Kooten¹,

Cetre²,

Ragland³

et al. 2022

Preprint

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The behavior of an adaptive optics (AO) system for ground-based high contrast imaging (HCI) dictates the achievable contrast of the instrument. In conditions where the coherence time of the atmosphere is short compared to the speed of the AO system, the servo-lag error can become the dominant error term of the AO system. While the AO system measures the wavefront error and subsequently applies a correction (typically taking a total of one or a few milliseconds), the atmospheric turbulence above the telescope has changed resulting in the servolag error. In addition to reducing the Strehl ratio, the servo-lag error causes a build-up of speckles along the direction of the dominant wind vector in the coronagraphic image, severely limiting the contrast at small angular separations. One strategy to mitigate this problem is to predict the evolution of the turbulence over the delay time. Our predictive wavefront control algorithm minimizes, in a mean square sense, the wavefront error over the delay and has been implemented on the Keck II AO bench. In this paper, we report on the latest results of our algorithm and discuss updates to the algorithm itself. We explore how to tune various filter parameters based on both daytime laboratory tests and on-sky tests. We show a reduction in residual-mean-square wavefront error for the predictor compared to the leaky integrator (the standard controller for Keck) implemented on Keck for three separate nights. Finally, we present contrast improvements for daytime and on-sky tests for the first time.Using the L-band vortex coronagraph for Keck's NIRC2 instrument, we find a contrast gain of up to 2 at a separation of 3 λ/D and up to 3 for larger separations (3-7λ/D).

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The Santa Cruz Extreme AO Lab (SEAL): design and first light

Cited by 7 publications

References 8 publications

Laboratory demonstration of real-time focal plane wavefront control of residual atmospheric speckles

Laboratory demonstration of real-time focal plane wavefront control of residual atmospheric speckles

Laboratory Demonstration of Real-Time Focal Plane Wavefront Control of Residual Atmospheric Speckles

Predictive wavefront control on Keck II adaptive optics bench: on-sky coronagraphic results

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