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A Mach-Zehnder inte...
A Mach-Zehnder interferometer based on orbital angular momentum for improved vortex coronagraph efficiency
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- Piron, P. (author)
- Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium.
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- Delacroix, C. (author)
- Ctr Rech Lyon CRAL, High Angular Resolut & Stellar Surroundings Astro, F-69561 St Genis Laval, France.
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- Huby, E. (author)
- Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium.
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- Mawet, D. (author)
- CALTECH, Dept Astron, Pasadena, CA 91125 USA.
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- Karlsson, Mikael (author)
- Uppsala universitet,Tillämpad materialvetenskap
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- Ruane, G. (author)
- Rochester Inst Technol, Chester F Carlson Ctr Imaging Sci, Rochester, NY 14623 USA.
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- Habraken, S. (author)
- Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium.
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- Absil, O. (author)
- Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium.
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- Surdej, J. (author)
- Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium.
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Univ Liege, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium Ctr Rech Lyon CRAL, High Angular Resolut & Stellar Surroundings Astro, F-69561 St Genis Laval, France. (creator_code:org_t)
- SPIE, 2015
- 2015
- English.
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In: Techniques And Instrumentation For Detection Of Exoplanets Vii. - : SPIE. - 9781628417715
- Related links:
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https://orbi.uliege....
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
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- The Annular Groove Phase Mask (AGPM) is a vectorial vortex phase mask. it act, as a half-wave plate with a radial fast axis orientation operating in the mid infrared domain. When placed at the the focus of a telescope element provides a continuous helical phase ramp for an on axis sources, which creates the orbital angular momentum. Thanks to that phase, the intensity of the central source is canceled by a down-stream pupil stop, while the off axis sources are not affected. However due to experimental conditions the nulling is hardly perfect. To improve the null, a Mach-Zehnder interferometer containing Dove prisms differently oriented can be proposed to sort out light based on its orbital angular momentum (OAM). Thanks to the differential rotation of the beam, a 7 phase shift is achieved for the on axis light affected by a non zero OAM Therefore the contrast between the star and its faint companion is enhanced. Nevertheless, due the Dove prisms birefringence, the performance of the interferometer is relatively poor. To solve this problem, we propose to add a birefringent wave-plate in each arm to compensate this birefringence. In this paper, we will develop the mathematical model of the wave front using the Jones formalism. The performance of the interferometer is at first computed for the simple version without the birefringent plate. Then the effect of the birefringent plate is be mathematically described and the performance is re-computed.
Subject headings
- NATURVETENSKAP -- Fysik -- Acceleratorfysik och instrumentering (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Accelerator Physics and Instrumentation (hsv//eng)
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Keyword
- Orbital angular momentum
- Coronagraphy
- Interferometry
- Birefringence
- Polarization
Publication and Content Type
- ref (subject category)
- kon (subject category)
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