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Proceedings Paper • Open Access

Polarization scramblers in Earth observing spectrometers: lessons learned from Sentinel-4 and 5 phases A/B1
Author(s): Jérôme Caron; Jean-Loup Bézy; Grégory Bazalgette Courrèges-Lacoste; Bernd Sierk; Roland Meynart; Michael Richert; Didier Loiseaux

Paper Abstract

Sensitivity to polarization is a major design driver for Earth observing dispersive spectrometers. While the measured Earth radiance observed from space in the UV, visible and near IR bands has a strong and highly variable linearly polarized component, most essential components in spectrometers are inherently sensitive to polarization: scan mirrors, gratings, dichroics. Minimisation of the resulting radiometric errors is a challenge and cannot be only achieved with careful optical designs. Depolarization by passive optical components such as birefringent polarization scramblers has been demonstrated with the last generation of atmosphere monitoring instruments (MERIS, OMI). In order to achieve the demanding performances targeted by future instruments (Sentinel-4, Sentinel-5, CarbonSat) the available degrees of freedom left for optimisation shall be explored, and new polarization scrambler designs must be found.

This paper summarizes design rules and performance aspects identified by ESA during phases A/B1 of the Sentinel-4 and Sentinel-5 missions. The following aspects have been investigated and will be discussed: minimization of polarization dependent spectral oscillations, use of a polarization scrambler in converging beam or parallel beam at large angles of incidence, polarization dependent pointing error.

Paper Details

Date Published: 20 November 2017
PDF: 9 pages
Proc. SPIE 10564, International Conference on Space Optics — ICSO 2012, 105642B (20 November 2017); doi: 10.1117/12.2309044
Show Author Affiliations
Jérôme Caron, European Space Agency (Netherlands)
Jean-Loup Bézy, European Space Agency (Netherlands)
Grégory Bazalgette Courrèges-Lacoste, European Space Agency (Netherlands)
Bernd Sierk, European Space Agency (Netherlands)
Roland Meynart, European Space Agency (Netherlands)
Michael Richert, EADS Sodern (France)
Didier Loiseaux, EADS Sodern (France)

Published in SPIE Proceedings Vol. 10564:
International Conference on Space Optics — ICSO 2012
Bruno Cugny; Errico Armandillo; Nikos Karafolas, Editor(s)

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