مؤتمر
Vortex phase masks of topological charge 4 and higher with diamond subwavelength gratings
| العنوان: | Vortex phase masks of topological charge 4 and higher with diamond subwavelength gratings |
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| المؤلفون: | König, Lorenzo, Absil, Olivier, Delacroix, Christian, Lobet, Michaël, Karlsson, Mikael, Vargas Catalán, Ernesto, Orban De Xivry, Gilles, Loicq, Jerôme, Habraken, Serge |
| المساهمون: | STAR - Space sciences, Technologies and Astrophysics Research - ULiège |
| المصدر: | Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV, 1145144 (2020-12-13); SPIE Astronomical Telescopes + Instrumentation 2020, 14 - 18 Dec 2020 |
| بيانات النشر: | SPIE, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | extrasolar planet, high-contrast imaging, small inner working angle, vector vortex coronagraph, subwavelength grating, phase mask, metasurfaces, Physical, chemical, mathematical & earth Sciences, Space science, astronomy & astrophysics, Physique, chimie, mathématiques & sciences de la terre, Aérospatiale, astronomie & astrophysique |
| الوصف: | High contrast imaging at small inner working angles can be achieved using a vector vortex coronagraph in the focal plane of the telescope providing a helical phase ramp with a singularity at its center. The form birefringence of full-diamond subwavelength gratings has proven to be well suited to manufacture such vortex phase masks for coronagraphic applications (Subwavelength Grating Vortex Coronagraph, SGVC). In the past years our group has developed and manufactured SGVCs of topological charge 2 (Annular Groove Phase Mask, AGPM) made of a concentric diamond subwavelength grating. For future applications including ELT-class telescopes in the near- to mid-infrared that will partly resolve nearby stars, it is however useful to increase the topological charge of the vortex. After shortly reviewing our previous attempts at optimizing the grating structure for SGVC of charge 4, we present the first laboratory results obtained with such devices. We then introduce and discuss more realistic simulations compared to prior studies using finite-difference time-domain methods. The quality of the simulation results obtained with the open source software MEEP for an AGPM is shown to be appropriate for developing and assessing the performance of future vortex phase masks. We therefore perform updated simulations for SGVC of charge 4 including various designs with straight and curved grating lines. We conclude with a perspective on the potential of metasurfaces and their applications to design novel vortex coronagraphs based on subwavelength structures. EPIC |
| نوع الوثيقة: | conference paper http://purl.org/coar/resource_type/c_5794 conferenceObject |
| اللغة: | English |
| Relation: | info:eu-repo/grantAgreement/EC/H2020/819155; https://ui.adsabs.harvard.edu/abs/2020SPIE11451E..44K |
| DOI: | 10.1117/12.2576166 |
| URL الوصول: | https://orbi.uliege.be/handle/2268/259405 |
| حقوق: | open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess |
| رقم الأكسشن: | edsorb.259405 |
| قاعدة البيانات: | ORBi |
| DOI: | 10.1117/12.2576166 |
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