Ingot wavefront sensor: from the Fourier End2End numerical simulation to the LOOPS test bench

Arcidiacono, Carmelo; Filippo, Simone Di; Greggio, Davide; Santakumari, Kalyan Kumar Radhakrishnan; Portaluri, Elisa; Bergomi, Maria; Viotto, Valentina; Magrin, Demetrio; Ragazzoni, Roberto; Marafatto, Luca; Dima, Marco; Farinato, Jacopo; Janin-Potiron, Pierre; Fusco, Thierry; Neichel, Benoît; Fauvarque, Olivier; Schatz, Lauren

doi:10.1117/12.2562355

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…In this work, we focus on Shack-Hartmann wave-front sensing (SHWFS) because it is currently the best suited WFS for LGSWFS. Although alternative solutions, such as Pyramid 3 and Ingot WFS, 4 exist and are pursued actively, 5,6 they still have to be proved on the sky and are therefore deemed not mature enough to be used within the ELT. Despite being a forced choice for LGS sensing, the SHWFS in the context of ELT has a major downside as it requires a detector with a large number of pixels to satisfy at the same time the requirement on the extended spot sampling, both in term of pixel pitch and overall FOV, and on turbulence spatial sampling.…”

Section: Introductionmentioning

confidence: 99%

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Fusco

Agapito

Neichel

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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Laser guide star (LGS) wave-front sensing (LGSWFS) is a key element of tomographic adaptive optics system. However, when considering Extremely Large Telescope (ELT) scales, the LGS spot elongation becomes so large that it challenges the standard recipes to design LGSWFS. For classical Shack-Hartmann wave-front sensor (SHWFS), which is the current baseline for all ELT LGS-assisted instruments, a trade-off between the pupil spatial sampling [number of sub-apertures (SAs)], the SA field-of-view (FoV) and the pixel sampling within each SA is required. For ELT scales, this trade-off is also driven by strong technical constraints, especially concerning the available detectors and in particular their number of pixels. For SHWFS, a larger field of view per SA allows mitigating the LGS spot truncation, which represents a severe loss of performance due to measurement biases. For a given number of available detectors pixels, the SA FoV is competing with the proper sampling of the LGS spots, and/or the total number of SAs. We proposed a sensitivity analysis, and we explore how these parameters impacts the final performance. In particular, we introduce the concept of super resolution, which allows one to reduce the pupil sampling per WFS and opens an opportunity to propose potential LGSWFS designs providing the best performance for ELT scales.

show abstract

Section: Introductionmentioning

confidence: 99%

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Fusco

Agapito

Neichel

et al. 2022

J. Astron. Telesc. Instrum. Syst.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In this work we focus on Shack-Hartmann WFS because it is currently the best suited WFS for LGS WFSensing. Although alternative solutions, like Pyramid 3 and Ingot WFS, 4 exist and are pursued actively, 5,6 they still have to be proved on sky and are therefore deemed not mature enough to be used within the ELT. Despite being a forced choice for LGS sensing, the SHWFS in the context of ELT has a major downside as it requires a detector with a large number of pixels to satisfy at the same time the requirement on the extended spot sampling, both in term of pixel pitch and overall FoV, and on turbulence spatial sampling.…”

Section: Introductionmentioning

confidence: 99%

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Fusco,

Agapito,

Neichel

et al. 2022

Preprint

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Laser Guide Star [LGS] wave-front sensing [LGSWFS] is a key element of tomographic Adaptive Optics system. However, when considering Extremely Large Telescope [ELT] scales, the LGS spot elongation becomes so large that it challenges the standard recipes to design LGSWFS. For classical Shack-Hartmann Wave-Front Sensor [SHWFS], which is the current baseline for all ELT LGS-assisted instruments, a trade-off between the pupil spatial sampling (number of sub-apertures), the sub-aperture field-of-view and the pixel sampling within each sub-aperture is required. For ELT scales, this trade-off is also driven by strong technical constraints, especially concerning the available detectors and in particular their number of pixels. For SHWFS, a larger field of view per sub-aperture allows mitigating the LGS spot truncation, which represents a severe loss of performance due to measurement biases. For a given number of available detectors pixels, the sub-aperture Field of View [FoV] is competing with the proper sampling of the LGS spots, and/or the total number of sub-apertures. In this paper we propose a sensitivity analysis, and we explore how these parameters impacts the final performance. In particular we introduce the concept of super resolution, which allows to reduce the pupil sampling per WFS, and opens an opportunity to propose potential LGSWFS designs providing the best performance for ELT scales.

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“…Lastly, having equipped the bench with a deformable lens to be used as an aberrator, we defined a calibration/reconstruction procedure to investigate the response of the I-WFS when known aberrations are applied. For more detailed information about the I-WFS, we direct the reader to the original papers [5][6][7][8] and further developments. [9][10][11][12][13][14] Further author information: simone.difilippo@inaf.it arXiv:2209.12921v1 [astro-ph.IM] 26 Sep 2022…”

Section: Introductionmentioning

confidence: 99%

Laboratory testing of the Ingot WFS

Filippo

Greggio

Bergomi

et al. 2022

Adaptive Optics Systems VIII

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The ingot WFS is a new kind of wavefront sensor specifically designed to deal with the elongation of LGS reference sources on ELT-class telescopes. Like the pyramid, it belongs to the family of pupil plane wavefront sensors and can be considered as a generalization of the pyramid WFS for extended, three-dimensional elongated sources. The current design uses a simple, reflective roof-shaped prism to split the light into three pupils that are used to retrieve the wavefront shape. A test-bench has been realized at the INAF-Padova laboratories to test the alignment and functioning of the ingot. The bench is equipped with a deformable lens, conjugated to the pupil plane, able to apply low-order aberrations and with a hexapod for the precise alignment of the ingot prism. In this work we present a robust and fully automated Python-code alignment procedure, which is able, by using the optical feedback from the I-WFS, to adjust its 6-degrees of freedom. Moreover, we report on the tests conducted with the deformable lens to characterize the ingot WFS response to low-order aberrations in terms of sensitivity and linearity. The results are used as a comparison for simulations to validate the ray-tracing modeling approach with the future goal of optimizing the procedure adopted for signal calculation and phase retrieval.

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Ingot wavefront sensor: from the Fourier End2End numerical simulation to the LOOPS test bench

Cited by 3 publications

References 13 publications

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Key wavefront sensors features for laser-assisted tomographic adaptive optics systems on the Extremely Large Telescope

Laboratory testing of the Ingot WFS

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