High contrast internal and external coronagraph masks produced by various techniques

Balasubramanian, Kunjithapatham; Wilson, Daniel W.; White, Victor; Muller, Richard E.; Dickie, Matthew R.; Yee, Karl; Ruiz, R.; Shaklan, Stuart; Cady, Eric; Kern, Brian; Belikov, Ruslan; Guyon, Olivier; Kasdin, N. Jeremy

doi:10.1117/12.2024615

Cited by 13 publications

(7 citation statements)

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“…The choice of polymethylglutarimide (PMGI) as the dielectric is driven by the MDL's current HLC manufacturing capabilities; PMGI outside of the occulter mask results in incoherent light, so we limit the inclusion of dielectric to the occulter mask only. Dielectric deposition on the mask and shaping technologies limit what dielectric material is to be used; 43,44 other materials have been considered for this application, 11,45 we, however, limit ourselves to the Roman coronagraph material. The resolution at the pupil planes drives the computing time; we compute the minimum resolution to give a reliable result at high contrast to be ∼200 pixels across the pupil and use 250 pixels for margin.…”

Section: Our Case Study: the Roman Coronagraph Hlcmentioning

confidence: 99%

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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Section: Our Case Study: the Roman Coronagraph Hlcmentioning

confidence: 99%

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 achromatic focal plane mask was manufactured at the NASA Jet Propulsion Laboratory Microdevices Laboratory, as described in Balasubramanian et al [5]. The mask was made from PMGI (Poly methyl glutarimide) resist on Silicon with an Aluminum coating, which makes it entirely reflective.…”

Section: Focal Plane Mask Designmentioning

confidence: 99%

Performance of an achromatic focal plane mask for exoplanet imaging coronagraphy

et al. 2014

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Coronagraph technology combined with wavefront control is close to achieving the contrast and inner working angle requirements in the lab necessary to observe the faint signal of an Earth-like exoplanet in monochromatic light. An important remaining technological challenge is to achieve high contrast in broadband light. Coronagraph bandwidth is largely limited by chromaticity of the focal plane mask, which is responsible for blocking the stellar PSF. The size of a stellar PSF scales linearly with wavelength; ideally, the size of the focal plane mask would also scale with wavelength. A conventional hard-edge focal plane mask has a fixed size, normally sized for the longest wavelength in the observational band to avoid starlight leakage. The conventional mask is oversized for shorter wavelengths and blocks useful discovery space. Recently we presented a solution to the size chromaticity challenge with a focal plane mask designed to scale its effective size with wavelength. In this paper, we analyze performance of the achromatic size-scaling focal plane mask within a Phase Induced Amplitude Apodization (PIAA) coronagraph. We present results from wavefront control around the achromatic focal plane mask, and demonstrate the size-scaling effect of the mask with wavelength. The edge of the dark zone, and therefore the inner working angle of the coronagraph, scale with wavelength. The achromatic mask enables operation in a wider band of wavelengths compared with a conventional hard-edge occulter.

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“…Instead, the mask was made reflective, with nominally-open region coated with reflective metal and the dark region created from a highly-absorbing material: black silicon. 16 The manufacturing of this mask and associated model validation was the subject of WFIRST-AFTA Coronagraph Milestone 1, and is covered in more detail in Ref. 8 Results are normalized such that the peak brightness of the PSF is 1 and displayed on a log 10 scale.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of high contrast with an obscured aperture with the WFIRST-AFTA shaped pupil coronagraph

Cady

Prada

et al. 2015

J. Astron. Telesc. Instrum. Syst

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The coronagraph instrument on the WFIRST-AFTA mission study has two coronagraphic architectures, shaped pupil and hybrid Lyot, which may be interchanged for use in different observing scenarios. Each architecture relies on newly-developed mask components to function in the presence of the AFTA aperture, and so both must be matured to a high technology readiness level (TRL) in advance of the mission. A series of milestones were set to track the development of the technologies required for the instrument; in this paper, we report on completion of WFIRST-AFTA Coronagraph Milestone 2-a narrowband 10 −8 contrast test with static aberrations for the shaped pupil-and the plans for the upcoming broadband Coronagraph Milestone 5.

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High contrast internal and external coronagraph masks produced by various techniques

Cited by 13 publications

References 0 publications

Coronagraph design with the electric field conjugation algorithm

Coronagraph design with the electric field conjugation algorithm

Performance of an achromatic focal plane mask for exoplanet imaging coronagraphy

Demonstration of high contrast with an obscured aperture with the WFIRST-AFTA shaped pupil coronagraph

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