Fundamental limits to high-contrast wavefront control

Mazoyer, J.; Pueyo, Laurent

doi:10.1117/12.2274657

Cited by 3 publications

(1 citation statement)

References 23 publications

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“…The position z can be optimized considering the size of the chosen dark hole, the number of actuators, the level of phase and amplitude aberrations to be corrected and the bandwidth of observation. Several authors have analyzed in detail these dependencies to find the optimal position of the DMs [146][147][148][149][150]. Normalized intensity limits for the one or two DM cases are recalled in [34].…”

Section: Full Dark Hole Using Two Deformable Mirrors In Cascadementioning

confidence: 99%

Imaging exoplanets with coronagraphic instruments

Galicher¹,

Mazoyer²

2024

Comptes Rendus. Physique

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Exoplanetary science is a very active field of astronomy nowadays, with questions still opened such as how planetary systems form and evolve (occurrence, process), why such a diversity of exoplanets is observed (mass, radius, orbital parameters, temperature, composition), and what are the interactions between planets, circumstellar disk and their host star. Several complementary methods are used for the detection of exoplanets. Among these, imaging aims at the direct detection of the light reflected, scattered or emitted by exoplanets and circumstellar disks. This allows their spectral and polarimetric characterization. Such imaging remains challenging because of the large luminosity ratio (10 4 -10 10 ) and the small angular separation (fraction of an arcsecond) between the star and its environment. Over the past two decades, numerous techniques, including coronagraphy, have been developed to make exoplanet imaging a reality.This paper gives a broad overview of the subsystems that make up a coronagraphic instrument for imaging exoplanetary systems. It is especially intended for non-specialists or newcomers in the field. We explain the principle of coronagraphy and propose a formalism to understand their behavior. We discuss the impact of wavefront aberrations on the performance of coronagraphs and how they induce stellar speckles in the scientific image. Finally, we present instrumental and signal processing techniques used for on-sky minimization or a posteriori calibration of these speckles in order to improve the performance of coronagraphs.Résumé. L'exoplanétologie est un domaine très actif de l'astronomie moderne avec des questions encore ouvertes : comment les systèmes planétaires se forment-ils et évoluent-ils ; pourquoi une telle diversité d'exoplanètes est-elle observée (masse, rayon, paramètres orbitaux, température, composition) ; quelles sont les interactions entre les planètes, les disques circumstellaires et leur étoile hôte ? Plusieurs méthodes complémentaires sont utilisées pour la détection d'exoplanètes. Parmi celles-ci, l'imagerie permet la détection directe de la lumière réfléchie, diffusée ou émise par les exoplanètes et les disques circumstellaires. Ceci permet une caractérisation spectrale et polarimétrique. Obtenir une image d'exoplanète n'est cependant pas simple en raison du grand rapport de luminosité (10 4 -10 10 ) et de la faible séparation angulaire (fraction de seconde d'angle) entre l'étoile et son environnement. Depuis deux décennies, de nombreuses techniques, dont la coronographie, ont été développées pour faire de l'imagerie des exoplanètes une réalité.

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Section: Full Dark Hole Using Two Deformable Mirrors In Cascadementioning

confidence: 99%

Imaging exoplanets with coronagraphic instruments

Galicher¹,

Mazoyer²

2024

Comptes Rendus. Physique

Self Cite

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Advances in optical engineering for future telescopes

Kim¹,

Choi²,

Brendel³

et al. 2021

OEA

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Significant optical engineering advances at the University of Arizona are being made for design, fabrication, and construction of next generation astronomical telescopes. This summary review paper focuses on the technological advances in three key areas. First is the optical fabrication technique used for constructing next-generation telescope mirrors. Advances in ground-based telescope control and instrumentation comprise the second area of development. This includes active alignment of the laser truss-based Large Binocular Telescope (LBT) prime focus camera, the new MOBI-US modular cross-dispersion spectroscopy unit used at the prime focal plane of the LBT, and topological pupil segment optimization. Lastly, future space telescope concepts and enabling technologies are discussed. Among these, the Nautilus space observatory requires challenging alignment of segmented multi-order diffractive elements. The OASIS terahertz space telescope presents unique challenges for characterizing the inflatable primary mirror, and the Hyperion space telescope pushes the limits of high spectral resolution, far-UV spectroscopy. The Coronagraphic Debris and Exoplanet Exploring Pioneer (CDEEP) is a Small Satellite (SmallSat) mission concept for high-contrast imaging of circumstellar disks and exoplanets using vector vortex coronagraph. These advances in optical engineering technologies will help mankind to probe, explore, and understand the scientific beauty of our universe.

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Active Correction of Aperture Discontinuities-Optimized Stroke Minimization. II. Optimization for Future Missions

Mazoyer

Pueyo

N’Diaye

et al. 2017

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High-contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. Instrumentation techniques in this field have greatly improved over the last two decades, with the development of stellar coronagraphy, in parallel with specific methods of wavefront sensing and control. Next generation space-and ground-based telescopes will allow the characterization cold solar-system like planets for the first time and maybe even in situ detection of bio-markers. However, the growth of primary mirror diameters, necessary for these detection, comes with an increase of their complexity (segmentation, secondary mirror features). These discontinuities in the aperture can greatly limit the performance of coronagraphic instruments. In this context, we introduced a new technique, Active Correction of Aperture Discontinuities -Optimized Stroke Minimization (ACAD-OSM), to correct for the diffractive effects of aperture discontinuities in the final image plane of a coronagraph, using deformable mirrors. In this paper, we present several tools that can be used to optimize the performance of this technique for its application to future large missions. In particular, we analyze the influence of the deformable setup (size and separating distance) and found that there is an optimal point for this setup, optimizing the performance of the instrument in contrast and throughput while minimizing the strokes applied to the deformable mirrors. These results will help us design future coronagraphic instruments to obtain the best performance.

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Fundamental limits to high-contrast wavefront control

Cited by 3 publications

References 23 publications

Imaging exoplanets with coronagraphic instruments

Imaging exoplanets with coronagraphic instruments

Advances in optical engineering for future telescopes

Active Correction of Aperture Discontinuities-Optimized Stroke Minimization. II. Optimization for Future Missions

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