Numerical modeling of the Habex coronagraph

Krist, John; Martin, Stefan; Kuan, Gary M.; Mennesson, Bertrand; Ruane, Garreth; Saini, Navtej; Trauger, John T.; Breckinridge, James B.; Mawet, Dimitri; Stahl, Phil; Davis, Jeffrey

doi:10.1117/12.2530462

Cited by 12 publications

(11 citation statements)

References 6 publications

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“…The DM quilting, i.e., the phase pattern on the DM surface, induces a square grid of bright spots at∼30 λ/D. This effect is only concerning at levels of raw contrast below´-1 10 9 (Krist et al 2019). 4.…”

Section: Results For the Avc In Monochromatic Lightmentioning

confidence: 99%

High-contrast Demonstration of an Apodized Vortex Coronagraph

Llop-Sayson

Ruane

Mawet

et al. 2020

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High-contrast imaging is the primary path to the direct detection and characterization of Earth-like planets around solar-type stars; a cleverly designed internal coronagraph suppresses the light from the star, revealing the elusive circumstellar companions. However, future large-aperture telescopes (>4 m in diameter) will likely have segmented primary mirrors, which cause additional diffraction of unwanted stellar light. Here we present the first high-contrast laboratory demonstration of an apodized vortex coronagraph, in which an apodizer is placed upstream of a vortex focal plane mask to improve its performance with a segmented aperture. The gray-scale apodization is numerically optimized to yield a better sensitivity to faint companions assuming an aperture shape similar to the LUVOIR-B concept. Using wavefront sensing and control over a one-sided dark hole, we achieve a raw contrast of 2×10 −8 in monochromatic light at 775nm, and a raw contrast of 4×10 −8 in a 10% bandwidth. These results open the path to a new family of coronagraph designs, optimally suited for next-generation segmented space telescopes.Unified Astronomy Thesaurus concepts: Exoplanets (498); Direct imaging (387); Space telescopes (1547)

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Section: Results For the Avc In Monochromatic Lightmentioning

confidence: 99%

High-contrast Demonstration of an Apodized Vortex Coronagraph

Llop-Sayson

Ruane

Mawet

et al. 2020

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“…The requirements for the HabEx coronagraph, for instance, include 64 × 64 DMs which translates to n act ¼ 59 assuming 62 actuators across the EP and Γ ¼ 0.95. 25 This increases n act by a factor of 59∕25.7 ¼ 2.3 and, by Eq. (5), scales the stellar intensity by 1.11ð25.7∕59Þ 2 ¼ 0.21, where the factor of 1.11 is due to the widening of the transfer function profile.…”

Section: Requirements On the Dm Electronicsmentioning

confidence: 94%

Microelectromechanical deformable mirror development for high-contrast imaging, part 2: the impact of quantization errors on coronagraph image contrast

Ruane

Echeverri

Bendek

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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Stellar coronagraphs rely on deformable mirrors (DMs) to correct wavefront errors and create high-contrast images. Imperfect control of the DM limits the achievable contrast, and therefore, the DM control electronics must provide fine surface height resolution and low noise. We study the impact of quantization errors due to the DM electronics on the image contrast using experimental data from the High Contrast Imaging Testbed facility at NASA's Jet Propulsion Laboratory. We find that the simplest analytical model gives optimistic predictions compared to real cases, with contrast up to 3 times better, which leads to DM surface height resolution requirements that are incorrectly relaxed by 70%. We show that taking into account the DM actuator shape, or influence function, improves the analytical predictions. However, we also find that end-to-end numerical simulations of the wavefront sensing and control process provide the most accurate predictions and recommend such an approach for setting robust requirements on the DM control electronics. From our experimental and numerical results, we conclude that a surface height resolution of ∼6 pm is required for imaging temperate terrestrial exoplanets around solar-type stars at wavelengths as small as 450 nm with coronagraph instruments on future space telescopes. Finally, we list the recognizable characteristics of quantization errors that may help determine if they are a limiting factor.

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“…Shaped dielectric is deposited on top of the metal occulter to control the phase of the wavefront thus adding extra degrees of freedom in the design. The HLC has the best performing record in terms of raw contrast in a vacuum testbed environment, 12 and, although it has been generally believed to suffer from sensitivity to low-order errors, 13 this has been mitigated through research for LUVOIR-A HLC designs. The requirements for LUVOIR and HabEx coronagraph instruments on raw contrast and sensitivity to low-order errors are remarkably strict.…”

Section: Introductionmentioning

confidence: 99%

“…[27][28][29] Furthermore, much progress is still needed to understand the limitations of coronagraph systems in a testbed environment. Indeed, the physical processes taking place at the optical elements and their interplay at very high contrast are poorly understood, e.g., the chromatic effects of the DM surface errors, 13 the DM actuator quantization effects, 30,31 or polarization-induced aberrations. 12,13,32 Modeling efforts at the Jet Propulsion Laboratory have been tackling the gap between simulation and testbed performance.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the physical processes taking place at the optical elements and their interplay at very high contrast are poorly understood, e.g., the chromatic effects of the DM surface errors, 13 the DM actuator quantization effects, 30,31 or polarization-induced aberrations. 12,13,32 Modeling efforts at the Jet Propulsion Laboratory have been tackling the gap between simulation and testbed performance. 12,33,34 The work presented here was done in the context of optimizing the design process for the Nancy Grace Roman Space Telescope (Roman) Coronagraph Instrument's HLC.…”

Section: Introductionmentioning

confidence: 99%

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Coronagraph design with the electric field conjugation algorithm

Llop-Sayson

Riggs

Mawet

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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The requirements for a coronagraph instrument to image and obtain spectra of rocky planets around bright stars from space are tight. Indeed, the goal of imaging an Earth-like planet requires a starlight suppression system that cancels light to a level of 10 −10 with sufficient stability and robustness to errors. Furthermore, the key science questions necessitate an adequate sample size; consequently, the throughput of the coronagraph drives the achievable yield of a given mission. The trade among achievable raw contrast, sensitivity to wavefront errors, and throughput poses a challenging problem in coronagraph design. The complexity of this problem drives us toward the simultaneous solving of all optical elements. We present a set of methods to optimize the design of a coronagraph. We implement these for the case of the hybrid Lyot coronagraph in the context of the Nancy Grace Roman Space Telescope Coronagraph Instrument. We discuss our findings in terms of coronagraph instrument design, and optical subsystems, and performance interplay.

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Numerical modeling of the Habex coronagraph

Cited by 12 publications

References 6 publications

High-contrast Demonstration of an Apodized Vortex Coronagraph

High-contrast Demonstration of an Apodized Vortex Coronagraph

Microelectromechanical deformable mirror development for high-contrast imaging, part 2: the impact of quantization errors on coronagraph image contrast

Coronagraph design with the electric field conjugation algorithm

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