Advanced control laws for the new generation of AO systems

Correia, Carlos

doi:10.1117/12.2313131

Cited by 2 publications

(2 citation statements)

References 48 publications

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“…This study gives insights into the instrument operations, essential to designing optimal post-processing techniques or AO predictive control tools that both aim to get rid of the servolag error signature (e.g. Males & Guyon 2018;Correia 2018). This effect is also important to design the next generation of high contrast instruments (e.g.…”

Section: Discussionmentioning

confidence: 99%

Origin of the asymmetry of the wind driven halo observed in high-contrast images

Cantalloube

Por

Dohlen

et al. 2018

A&A

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The latest generation of high contrast instruments dedicated to exoplanets and circumstellar disks imaging are equipped with extreme adaptive optics and coronagraphs to reach contrasts of up to 10 −4 at a few tenths of arc-seconds in the near infrared. The resulting image shows faint features, only revealed with this combination, such as the wind driven halo. The wind driven halo is due to the lag between the adaptive optics correction and the turbulence speed over the telescope pupil. However we observe an asymmetry of this wind driven halo that was not expected when the instrument was designed. In this letter, we describe and demonstrate the physical origin of this asymmetry and support our explanation by simulating the asymmetry with an end-to-end approach. From this work, we found out that the observed asymmetry is explained by the interference between the AO-lag error and scintillation effects, mainly originating from the fast jet stream layer located at about 12 km in altitude. Now identified and interpreted, this effect can be taken into account for further design of high contrast imaging simulators, next generation or upgrade of high contrast instruments, predictive control algorithms for adaptive optics or image post-processing techniques.

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Section: Discussionmentioning

confidence: 99%

Origin of the asymmetry of the wind driven halo observed in high-contrast images

Cantalloube

Por

Dohlen

et al. 2018

A&A

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“…FAST modal gain optimization, 19 both for LOWFS and HOWFS control is also a key area to develop that we have already been working on with SEAL. 18 However, this approach requires characterizing the rejection transfer function 34 (i.e., which is defined for a given mode relative to its open-and closed-loop temporal PSDs, or PSD OL and PSD CL , respectively, as:…”

Section: Key Areas For Contrast Improvementmentioning

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.

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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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Advanced control laws for the new generation of AO systems

Cited by 2 publications

References 48 publications

Origin of the asymmetry of the wind driven halo observed in high-contrast images

Origin of the asymmetry of the wind driven halo observed in high-contrast images

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

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