Extreme adaptive optics simulations for EPICS

Korkiakoski, Visa; Vérinaud, Christophe

doi:10.1051/ao4elt/201003007

Cited by 6 publications

(7 citation statements)

References 6 publications

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“…First, we mention the earlier result achieved in the context of EPICS, the XAO instrument on the ELT in the case of four thick spiders. 39 It was reported therein that both the zonal and modal reconstructors provide the same quality in the presence of four spider legs. Apart from that, two important points were underlined: the light behind spiders needs to be used in the reconstruction; and the amount of modulation should not be too large, otherwise, the sensor loses its sensitivity to low-order modes.…”

Section: Map Reconstructor With Modal Control Of the Dmmentioning

confidence: 93%

Advanced wavefront reconstruction methods for segmented Extremely Large Telescope pupils using pyramid sensors

Hutterer

Shatokhina

Obereder

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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The generation of Extremely Large Telescopes (ELTs) with mirror diameters up to 40 m has thick secondary mirror support structures (also known as spider legs), which cause difficulties in the wavefront reconstruction process. These spider legs create areas where the information of the phase is disconnected on the wavefront sensor detector, leading to pupil fragmentation and a loss of data on selected subapertures. The effects on wavefront reconstruction are differential pistons between segmented areas, leading to poor wavefront reconstruction. The resulting errors make the majority of existing control algorithms unfeasible for telescope systems having spider legs incorporated. A solution, named the split approach, is presented, which suggests to separate reconstruction of segment piston modes from the rest of the wavefront. Further, two methods are introduced for the direct reconstruction of the segment pistons. Due to the separate handling of the piston offsets on the segments, the split approach makes any of the existing phase reconstruction algorithms developed for nonsegmented pupils suitable for wavefront control in the presence of telescope spiders. We present end-to-end simulation results showing accurate, stable, and extremely fast wavefront reconstruction for the first light instrument mid-infrared ELT imager and spectograph of the ELT that is currently under construction.

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Section: Map Reconstructor With Modal Control Of the Dmmentioning

confidence: 93%

Advanced wavefront reconstruction methods for segmented Extremely Large Telescope pupils using pyramid sensors

Hutterer

Shatokhina

Obereder

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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“…On the ESO's ELT, the pyramid sensor is planned in the Natural Guide Star (NGS) SCAO modes on the three first light instruments MICADO, 33 HARMONI, 34,35 and METIS, 36 in the NGS XAO mode on the planet imager EPICS, 37 and in the postfocal laser tomography adaptive optics (LTAO) module ATLAS. 38 On the GMT, the PWFS is assumed to be used in the NGS SCAO mode 39 and as truth sensor in the LTAO system.…”

Section: Pyramid Sensor Features Applications and Modern Challengesmentioning

confidence: 99%

Review on methods for wavefront reconstruction from pyramid wavefront sensor data

Shatokhina

Hutterer

Ramlau

2020

J. Astron. Telesc. Instrum. Syst.

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Pyramid wavefront sensors are planned to be a part of many instruments that are currently under development for the extremely large telescopes (ELT). The unprecedented scales of the upcoming ELT-era instruments are inevitably connected with serious challenges for wavefront reconstruction and control algorithms. Apart from the huge number of correcting elements to be controlled in real-time, real-life features such as the segmentation of the telescope pupil, the low wind effect, the nonlinearity of the pyramid sensor, and the noncommon path aberrations will have a significantly larger impact on the imaging quality in the ELT framework than they ever had before. We summarize various kinds of wavefront reconstruction algorithms for the pyramid wavefront sensor. Based on several forward models, different algorithms were developed in the last decades for linear and nonlinear wavefront correction. The core ideas of the algorithms are presented, and a detailed comparison of the presented methods with respect to underlying pyramid sensor models, computational complexities, and reconstruction qualities is given. In addition, we review the existing and possible solutions for the above-named real-life phenomena. At the same time, directions for further investigations are sketched.

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“…For ELTs, pyramid sensors show enhanced performance in real life settings, e.g., they provide the ability to sense differential piston modes induced by diffraction effects of realistic telescope spiders that support secondary mirrors and perform even under significant levels of non-common path aberrations [79,20]. Pyramid wavefront sensors are going to be included in many ELT instruments [5,12,79,20,31,30,45,51,53,54,80]. We would like to mention that, apart from astronomical applications, the pyramid wavefront sensor is also applied in adaptive loops in ophthalmology [10,13,15,43] and microscopy [42,44].…”

Section: Introductionmentioning

confidence: 99%

Real-time adaptive optics with pyramid wavefront sensors: part I. A theoretical analysis of the pyramid sensor model

2019

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We consider the mathematical background of the wavefront sensor type that is widely used in Adaptive Optics systems for astronomy, microscopy, and ophthalmology. The theoretical analysis of the pyramid sensor forward operators presented in this paper is aimed at a subsequent development of fast and stable algorithms for wavefront reconstruction from data of this sensor type. In our analysis we allow the sensor to be utilized in both the modulated and non-modulated fashion. We derive detailed mathematical models for the pyramid sensor and the physically simpler roof wavefront sensor as well as their various approximations. Additionally, we calculate adjoint operators which build preliminaries for the application of several iterative mathematical approaches for solving inverse problems such as gradient based algorithms, Landweber iteration or Kaczmarz methods.

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Extreme adaptive optics simulations for EPICS

Cited by 6 publications

References 6 publications

Advanced wavefront reconstruction methods for segmented Extremely Large Telescope pupils using pyramid sensors

Advanced wavefront reconstruction methods for segmented Extremely Large Telescope pupils using pyramid sensors

Review on methods for wavefront reconstruction from pyramid wavefront sensor data

Real-time adaptive optics with pyramid wavefront sensors: part I. A theoretical analysis of the pyramid sensor model

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