Graded coronagraphic masks for high-contrast near-infrared imaging

Carson, J.; Wilson, Daniel W.; Trauger, John T.

doi:10.1117/12.615935

Cited by 2 publications

(1 citation statement)

References 12 publications

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“…Similarly there is a phase difference of 2π between beams two and four. Beam two has phases ±π/2 so that between sets of beams (1, 3) and (2,4), the chop of ±π/2 produces alternate constructive and destructive interference of the planet light.…”

Section: Modeling Fluctuations In the Nullmentioning

confidence: 99%

Progress in testing exo-planet signal extraction on the TPF-I planet detection testbed

Martin¹,

Szwaykowski²,

Loya³

et al. 2006

Advances in Stellar Interferometry

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The Terrestrial Planet Finder Interferometer (TPF-I) concept is being studied at the Jet Propulsion Laboratory and the TPF-I Planet Detection Testbed has been developed to simulate the detection process for an earthlike planet orbiting a star within about 15 pc. The testbed combines four beams of infrared light simulating the operation of a dual chopped Bracewell interferometer observing a star and a faint planet. This paper describes the results obtained this year including nulling of the starlight on four input beams at contrast ratios up to 250,000 to 1, and detection of faint planet signals at contrast ratios with the star of 2 million to 1.

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Section: Modeling Fluctuations In the Nullmentioning

confidence: 99%

Progress in testing exo-planet signal extraction on the TPF-I planet detection testbed

Martin¹,

Szwaykowski²,

Loya³

et al. 2006

Advances in Stellar Interferometry

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Limits on achievable intensity reduction with an optical occulter

Wasylkiwskyj

Shiri

2011

J. Opt. Soc. Am. A

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Deep shadowing of a normally incident plane wave by an opaque circular disk is partially negated by the formation of a region of strong intensity surrounding the axis passing normally through the disk center. This local intensity enhancement, historically referred to as the Poisson Spot (also known as the Spot of Arago), has been the principal source of difficulties in applications where a significant reduction of the incident intensity is essential. In particular, the NASA Terrestrial Planet Finder's (TPF) mission requires suppression of direct starlight by at least 10 orders of magnitude over the entire visible spectral range. One technique that has been proposed for blocking the direct starlight is to use a rotationally symmetric disk with petallike segments along its boundary. We find that, even though such configurations could, indeed, theoretically provide the desired intensity reduction, they would require unreasonably small radii of curvature at the petals' tips (in the range of micrometers). When the radii of curvature are increased to 3 mm, the intensity reduction drops to a modest 5 to 6 orders of magnitude. Given that for the NASA's TPF mission the proposed occulter radius would be on the order of 25 m, even the 3 mm radius of curvature would be too small for any practical implementation. Further increases of the radius of curvature result in progressively poorer intensity suppression. As an alternative solution we propose an apodized circular disk. We show that with an optimized apodization function, intensity reductions of at least 10 orders of magnitude can be achieved over the entire visible spectral range. Numerical results are presented for parameters appropriate to the NASA TPF mission.

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Graded coronagraphic masks for high-contrast near-infrared imaging

Cited by 2 publications

References 12 publications

Progress in testing exo-planet signal extraction on the TPF-I planet detection testbed

Progress in testing exo-planet signal extraction on the TPF-I planet detection testbed

Limits on achievable intensity reduction with an optical occulter

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