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Proceedings Paper • Open Access

Linearly variable filters fabricated by magnetron sputtering technology
Author(s): Thomas Bégou; Frédéric Lemarquis; Antonin Moreau; Fabien Lemarchand; Holger Reus; Detlef Arhilger; Harro Hagedorn; Julien Lumeau

Paper Abstract

Variable filters, which central wavelength of the bandpass shifts along one dimension of the component, is a promising way to simplify and to miniaturize imaging spectrophotometer systems for spatial observation. In fact, by combining a dispersive element and a variable filter, it is possible to realize a spectral and a spatial filtering based on pushbroom technique. While there were numerous methods developed in order to produce variable filters, at this date, there is no simple, reliable and repeatable method. In this paper, we present a new method for the fabrication of variable filters based on plasma assisted reactive magnetron sputtering (PARMS).

Variable filters are obtained upon the variation of the thickness of some or all the layers deposited on the substrate. The layers are deposited using a Bühler HELIOS machine in order to benefit from the high stability of the deposition process. To insure a non-uniformity of the deposited layers, adapted masks are placed in front of the targets for the low and high refractive index materials. The uniformity of these layers is measured via a custom set-up allowing a local measurement of the transmission to perform a mapping of the transmission over the whole component aperture.

In this paper, we present the fabrication of layers and filters with variable thickness. Various types of thickness gradients are presented.

Paper Details

Date Published: 12 July 2019
PDF: 8 pages
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 1118084 (12 July 2019); doi: 10.1117/12.2536211
Show Author Affiliations
Thomas Bégou, Institut Fresnel (France)
Frédéric Lemarquis, Institut Fresnel (France)
Antonin Moreau, Institut Fresnel (France)
Fabien Lemarchand, Institut Fresnel (France)
Holger Reus, Bühler Leybold Optics (Germany)
Detlef Arhilger, Bühler Leybold Optics (Germany)
Harro Hagedorn, Bühler Leybold Optics (Germany)
Julien Lumeau, Institut Fresnel (France)

Published in SPIE Proceedings Vol. 11180:
International Conference on Space Optics — ICSO 2018
Zoran Sodnik; Nikos Karafolas; Bruno Cugny, Editor(s)

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