Sensitivity analysis for high-contrast imaging with segmented space telescopes

Leboulleux, Lucie; Pueyo, Laurent; Sauvage, Jean-François; Fusco, Thierry; Mazoyer, J.; Sivaramakrishnan, Anand; N’Diaye, Mamadou; Soummer, Rémi

doi:10.1117/12.2313904

Cited by 9 publications

(9 citation statements)

References 22 publications

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“…50,51 One thing that all of these studies have in common is that they define global WFE tolerances over the entire telescope pupil, where the segments have a random contribution to the overall aberrations. In this paper, we focus on analytically defining requirements on a segment-tosegment basis instead, using the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS), [52][53][54] which models the DH average contrast of a coronagraph on a segmented telescope as a function of the segment aberrations. We first introduce a new semi-analytical (SA) calculation method for the PASTIS matrix.…”

Section: Introductionmentioning

confidence: 99%

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Laginja

Soummer

Mugnier

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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This paper introduces an analytical method to calculate segment-level wavefront error (WFE) tolerances to enable the detection of faint extra-solar planets using segmentedaperture telescopes in space. This study provides a full treatment of the case of spatially uncorrelated segment phasing errors for segmented telescope coronagraphy, which has so far only been approached using ad-hoc Monte Carlo (MC) simulations. Instead of describing the wavefront tolerance globally for all segments, our method produces spatially dependent requirement maps. We relate the statistical mean contrast in the coronagraph dark hole to the standard deviation of the WFE of each individual segment on the primary mirror. This statistical framework for segment-level tolerancing extends the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS), which is based uniquely on a matrix multiplication for the optical propagation. We confirm our analytical results with MC simulations of end-to-end optical propagations through a coronagraph. Comparing our results for the Apodized Pupil Lyot Coronagraph designs for the Large Ultraviolet Optical Infrared telescope to previous studies, we show general agreement but we provide a relaxation of the requirements for a significant subset of segments in the pupil. These requirement maps are unique to any given telescope geometry and coronagraph design. The spatially uncorrelated segment tolerances we calculate are a key element of a complete error budget that will also need to include allocations for correlated segment contributions. We discuss how the PASTIS formalism can be extended to the spatially correlated case by deriving the statistical mean contrast and its variance for a nondiagonal aberration covariance matrix. The PASTIS tolerancing framework therefore brings a new capability that is necessary for the global tolerancing of future segmented space observatories.

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Section: Introductionmentioning

confidence: 99%

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Laginja

Soummer

Mugnier

et al. 2021

J. Astron. Telesc. Instrum. Syst.

Self Cite

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show abstract

“…50,51 One thing that all of these studies have in common is that they define global WFE tolerances over the entire telescope pupil, where the segments have a random contribution to the overall aberrations. In this paper, we focus on analytically defining requirements on a segment-to-segment basis instead, using the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS), 52,53,54 which models the dark hole average contrast of a coronagraph on a segmented telescope as a function of the segment aberrations. We first introduce a new semi-analytical (SA) calculation method for the PASTIS matrix.…”

Section: Introductionmentioning

confidence: 99%

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Laginja,

Soummer,

Mugnier

et al. 2021

Preprint

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This paper introduces an analytical method to calculate segment-level wavefront error tolerances in order to enable the detection of faint extra-solar planets using segmented-aperture telescopes in space. This study provides a full treatment of the case of spatially uncorrelated segment phasing errors for segmented telescope coronagraphy, which has so far only been approached using ad hoc Monte-Carlo simulations. Instead of describing the wavefront tolerance globally for all segments, our method produces spatially dependent requirement maps. We relate the statistical mean contrast in the coronagraph dark hole to the standard deviation of the wavefront error of each individual segment on the primary mirror. This statistical framework for segment-level tolerancing extends the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS), which is based uniquely on a matrix multiplication for the optical propagation. We confirm our analytical results with Monte-Carlo simulations of end-to-end optical propagations through a coronagraph. Comparing our results for the Apodized Pupil Lyot Coronagraph designs for the Large UltraViolet Optical InfraRed (LUVOIR) telescope to previous studies, we show general agreement but we provide a relaxation of the requirements for a significant subset of segments in the pupil. These requirement maps are unique to any given telescope geometry and coronagraph design. The spatially uncorrelated segment tolerances we calculate are a key element of a complete error budget that will also need to include allocations for correlated segment contributions. We discuss how the PASTIS formalism can be extended to the spatially correlated case by deriving the statistical mean contrast and its variance for a non-diagonal aberration covariance matrix. The PASTIS tolerancing framework therefore brings a new capability that is necessary for the global tolerancing of future segmented space observatories.

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“…Previous studies have determined cophasing requirements for large segmented apertures to be on the order of 10 pm over the full pupil, 8 with the objective of maintaining a DH contrast of 10 −10 . Instead of defining WFE tolerances over the entire telescope pupil, the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS) [9][10][11][12] allows us to derive segment-specific requirements, either for each segment individually when they are statistically independent from each other, or in the form of a segment covariance matrix when there are correlations between them. 13 The next step is to perform an experimental validation of these segment-level tolerances on a segmented mirror of a high contrast instrument in a laboratory setting to seek confirmation that they indeed yield the coronagraphic contrast they were calculated for.…”

Section: Introductionmentioning

confidence: 99%

Predicting contrast sensitivity to segmented aperture misalignment modes for the HiCAT testbed

Laginja,

Soummer,

Mugnier

et al. 2020

Preprint

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This paper presents the setup for empirical validations of the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS) tolerancing model for segmented coronagraphy. We show the hardware configuration of the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed on which these experiments will be conducted at an intermediate contrast regime between 10 −6 and 10 −8 . We describe the optical performance of the testbed with a classical Lyot coronagraph and describe the recent hardware upgrade to a segmented mode, using an IrisAO segmented deformable mirror. Implementing experiments on HiCAT is made easy through its top-level control infrastructure that uses the same code base to run on the real testbed, or to invoke the optical simulator. The experiments presented in this paper are run on the HiCAT testbed emulator, which makes them ready to be performed on actual hardware. We show results of three experiments with results from the emulator, with the goal to demonstrate PASTIS on hardware next. We measure the testbed PASTIS matrix, and validate the PASTIS analytical propagation model by comparing its contrast predictions to simulator results. We perform the tolerancing analysis on the optical eigenmodes (PASTIS modes) and on independent segments, then validate these results in respective experiments. This work prepares and enables the experimental validation of the analytical segment-based tolerancing model for segmented aperture coronagraphy with the specific application to the HiCAT testbed.

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Sensitivity analysis for high-contrast imaging with segmented space telescopes

Cited by 9 publications

References 22 publications

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Analytical tolerancing of segmented telescope co-phasing for exo-Earth high-contrast imaging

Predicting contrast sensitivity to segmented aperture misalignment modes for the HiCAT testbed

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