Multispectral filters assemblies for earth remote sensing imagers

Goff, Ronan Le; Krol, Hélène; Grèzes-Besset, Catherine; Lequime, Michel; Bégou, Thomas; Hecquet, Christophe; Zerrad, Myriam; Badoil, Bruno; Montay, G.; Gasc, Karine

doi:10.1117/12.2304107

Cited by 8 publications

(10 citation statements)

References 4 publications

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“…In particular, we have demonstrated complex bandpass filers within the framework of various space projects, e.g. IDEFIX, TARANIS or 3MI [4][5][6]. For these projects, deposition of multilayer stacks composed with more than one hundred layers with total thickness up to 25 µm were needed and filters with spectral performances which do not deviate from theory by more than a few percent over broad spectral ranges were demonstrated.…”

Section: Deposition Systemmentioning

confidence: 99%

Linearly variable filters fabricated by magnetron sputtering technology

Bégou

Lemarquis

Moreau

et al. 2019

International Conference on Space Optics — ICSO 2018

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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.

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Section: Deposition Systemmentioning

confidence: 99%

Linearly variable filters fabricated by magnetron sputtering technology

Bégou

Lemarquis

Moreau

et al. 2019

International Conference on Space Optics — ICSO 2018

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“…Since the end of the 1990s, the simultaneous availability of powerful optical filter design software [1][2][3][4] and reliable thin-film deposition techniques using energetic processes [5][6][7] such as ion beam assistance, ion beam sputtering or magnetron sputtering have made possible the manufacture of high performance optical interference coatings comprising a great number of layers, from one hundred [8] up to a few thousand [9,10]. For highly demanding applications such as observation of the Earth from space [11,12], wavelength multiplexing of high data rate optical telecommunications channels [13,14], study of the organization of living matter at the cellular scale [15], or interferometric detection of gravitational waves [16,17], it is necessary to confirm by very accurate measurements the theoretical figures provided by the design, especially for some key filter parameters like optical density in the blocking regions, steepness of band edges, or wavelength and angle resolved scattering.…”

Section: Introductionmentioning

confidence: 99%

Breakthrough spectrophotometric instrument for the ultra-fine characterization of the spectral transmittance of thin-film optical filters

Lequime¹,

Zerrad²,

Amra³

2018

Opt. Express

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In this paper, we provide a detailed description of the main features of the upgraded version of a spectrophotometric apparatus developed by our team since 2014 [Opt. Express 23, 26863 (2015)]), and whose improved performance allows the characterization over the visible and near infrared part of the spectrum of the transmittance of complex interference filters with high spectral resolution (approximately one tenth of a nanometer) and an extremely wide dynamic range (thirteen decades).

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“…For this, magnetron sputtering [2] is a very consistent deposition process that gives superior uniformity and is well suited for narrower bandpass filters around 20 nm.…”

Section: Multispectral Strip Filter Assembliesmentioning

confidence: 99%