Adapting the pyramid wavefront sensor for pupil fragmentation of the ELT class telescopes

Nicolas Levraud; Vincent Chambouleyron; Olivier Fauvarque; Mahawa Cisse; Jean-François Sauvage; Benoît Neichel; Charlotte Bond; Enrico Pinna; Simone Esposito; Noah Schwartz; Thierry Fusco

doi:10.1117/12.2629861

29 August 2022 Adapting the pyramid wavefront sensor for pupil fragmentation of the ELT class telescopes

Nicolas Levraud, Vincent Chambouleyron, Olivier Fauvarque, Mahawa Cisse, Jean-François Sauvage, Benoît Neichel, Charlotte Bond, Enrico Pinna, Simone Esposito, Noah Schwartz, Thierry Fusco

Author Affiliations +

Proceedings Volume 12185, Adaptive Optics Systems VIII; 1218559 (2022) https://doi.org/10.1117/12.2629861
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Conference Poster

Abstract

The next generation of Extremely Large Telescope (24 to 39m diameter) will suffer from the so-called ”pupil fragmentation” problem. Due to their pupil shape complexity (segmentation, large spiders...), some differential pistons may appear between some isolated part of the full pupil during the observations. Although classical AO system will be able to correct for turbulence effects, they will be blind to this specific telescope induced perturbations. Hence, such differential piston, a.k.a petal modes, will prevent to reach the diffraction limit of the telescope and ultimately will represent the main limitation of AO-assisted observation with an ELT. In this work we analyse the spatial structure of these petal modes and how it affects the ability of a Pyramid Wavefront sensor to sense them. Then we propose a variation around the classical Pyramid concept for increasing the WFS sensitivity to this particular modes. Nevertheless, We show that one single WFS can not accurately and simultaneously measure turbulence and petal modes. We propose a double path wavefront sensor scheme to solve this problem. We show that such a scheme, associated to a spatial filtering of residual turbulence in the second WFS path dedicated to petal mode sensing, allows to fully measure and correct for both turbulence and fragmentation effects and will eventually restore the full capability and spatial resolution of the future ELT.

Citation Download Citation

Nicolas Levraud, Vincent Chambouleyron, Olivier Fauvarque, Mahawa Cisse, Jean-François Sauvage, Benoît Neichel, Charlotte Bond, Enrico Pinna, Simone Esposito, Noah Schwartz, and Thierry Fusco "Adapting the pyramid wavefront sensor for pupil fragmentation of the ELT class telescopes", Proc. SPIE 12185, Adaptive Optics Systems VIII, 1218559 (29 August 2022); https://doi.org/10.1117/12.2629861

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available