Deep Contrast and Companion Detection Using the EvWaCo Test Bed Equipped with an Achromatic Focal Plane Mask and an Adjustable Inner Working Angle

Mary Angelie Alagao; Adithep Kawinkij; Christophe Buisset; Apirat Prasit; Thierry Lépine; Yves Rabbia; Anthony Berdeu; Éric Thiébaut; Maud Langlois; Michel Tallon; Supachai Awiphan; Eugene Semenko; Pakakaew Rittipruk; David Mkrtichian; Apichat Leckngam; Griangsak Thuammasorn; Pimol Kaewsamoeta; Anuphong Inpan; Teerawat Kuha; Auychai Laoyang; Worawat Somboonchai; Suchinno Kanthum; Saran Poshyachinda; Boonrucksar Soonthornthum

doi:10.3847/1538-3881/abe709

Journal articles

Deep Contrast and Companion Detection Using the EvWaCo Test Bed Equipped with an Achromatic Focal Plane Mask and an Adjustable Inner Working Angle

Mary Angelie Alagao ¹ Adithep Kawinkij ¹ Christophe Buisset ¹ Apirat Prasit ¹ Thierry Lépine ² Yves Rabbia ³ Anthony Berdeu ¹ Éric Thiébaut ⁴ Maud Langlois ⁴ Michel Tallon ⁴ Supachai Awiphan ¹ Eugene Semenko ¹ Pakakaew Rittipruk ¹ David Mkrtichian ¹ Apichat Leckngam ¹ Griangsak Thuammasorn ¹ Pimol Kaewsamoeta ¹ Anuphong Inpan ¹ Teerawat Kuha ¹ Auychai Laoyang ¹ Worawat Somboonchai ¹ Suchinno Kanthum ¹ Saran Poshyachinda ¹ Boonrucksar Soonthornthum ¹

1 NARIT - National Astronomical Research Institute of Thailand

2 LHC - Laboratoire Hubert Curien [Saint Etienne]

3 OCA - Observatoire de la Côte d'Azur

4 CRAL - Centre de Recherche Astrophysique de Lyon

Abstract : The evanescent wave coronagraph uses the principle of frustrated total internal reflection (FTIR) to suppress the light coming from the star and study its close environment. Its focal plane mask is composed of a lens and a prism placed in contact with each other to produce the coronagraphic effect. In this paper, we present the experimental results obtained using an upgraded focal plane mask of the Evanescent Wave Coronagraph (EvWaCo). These experimental results are also compared to the theoretical performance of the coronagraph obtained through simulations. Experimentally, we reach a raw contrast equal to a few 10-4 at a distance equal to 3 λ/D over the full I band (λc = 800 nm, Δλ/λ ≍ 20%) and equal to 4 λ/D over the full R band (λc = 650 nm, Δλ/λ ≍ 23%) in unpolarized light. However, our simulations show a raw contrast close to 10-4 over the full I band and R band at the same distance, thus confirming the theoretical achromatic advantage of the coronagraph. We also verify the stability of the mask through a series of contrast measurements over a period of 8 months. Furthermore, we measure the sensitivity of the coronagraph to the lateral and longitudinal misalignment of the focal plane mask and to the lateral misalignment of the Lyot stop.

Document type :

Journal articles

Domain :

Physics [physics] / Physics [physics] / Optics [physics.optics]

Physics [physics] / Astrophysics [astro-ph] / Instrumentation and Methods for Astrophysic [astro-ph.IM]

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https://hal-ujm.archives-ouvertes.fr/ujm-03272971
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Submitted on : Monday, June 28, 2021 - 5:44:11 PM
Last modification on : Tuesday, May 10, 2022 - 3:20:03 PM

Deep Contrast and Companion Detection Using the EvWaCo Test Bed Equipped with an Achromatic Focal Plane Mask and an Adjustable Inner Working Angle

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Deep Contrast and Companion Detection Using the EvWaCo Test Bed Equipped with an Achromatic Focal Plane Mask and an Adjustable Inner Working Angle

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