Reference : First manufactured diamond AGPM vector vortex for the L- and N-bands: metrology and e...
Scientific congresses and symposiums : Unpublished conference
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/88205
First manufactured diamond AGPM vector vortex for the L- and N-bands: metrology and expected performances
English
Delacroix, Christian mailto [Université de Liège - ULg > Département de physique > Optique - Hololab >]
Forsberg, Pontus [Uppsala University > > > >]
Karlsson, Mikael [Uppsala University > > > >]
Mawet, Dimitri [NASA/JPL > > > >]
Lenaerts, Cedric [Université de Liège - ULg > > CSL (Centre Spatial de Liège) >]
Habraken, Serge mailto [Université de Liège - ULg > Département de physique > Optique - Hololab >]
Absil, Olivier mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Hanot, Charles [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Surdej, Jean mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
28-Oct-2010
No
No
International
In the Spirit of Lyot 2010
25-29 october 2010
Observatoire de Paris-Meudon
Paris
France
[en] The AGPM (Annular Groove Phase Mask, Mawet et al. 2005) is an optical vectorial vortex coronagraph (or vector vortex) synthesized by a circular subwavelength grating, that is a grating with a period smaller than λ/n (λ being the observed wavelength and n the refractive index of the grating substrate). Since it is a phase mask, it allows to reach a high contrast with a small working angle. Moreover, its subwavelength structure provides a good achromatization over wide spectral bands. Recently, we have manufactured and measured our first N-band prototypes that allowed us to validate the reproducibility of the microfabrication process. Here, we present newly produced mid-IR diamond AGPMs in the N-band (~10 µm), and in the most wanted L-band (~3.5 µm). We first give an extrapolation of the expected coronagraph performances. We then present the manufacturing and measurement results, using diamond-optimized microfabrication techniques such as nano-imprint lithography (NIL) and reactive ion etching (RIE). Finally, the subwavelength grating profile metrology combines surface metrology (scanning electron microscopy, atomic force microscopy, white light interferometry) with diffractometry on an optical polarimetric bench and cross correlation with theoretical simulations using rigorous coupled wave analysis (RCWA).
VORTEX
Researchers
http://hdl.handle.net/2268/88205

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