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Proceedings Paper • Open Access

Optical coatings for the Tropomi UV channel
Author(s): Martijn Brouwer; Robin van Buuren; Niels Gawlitta; Semen Grabarnik; Nick van der Valk; Rob Vink; Hedser van Brug; Huib Visser

Paper Abstract

Earth observation measurements at wavelengths below 320nm are challenging due to the steep decrease of the earth irradiance towards shorter wavelengths. Stray light and ghosting of longer wave light can easily overwhelm the signals at short wavelengths. In the UV channel (270-320nm) of the TROPOMI instrument this challenge has been addressed using a number of coatings. Three black UV mirror coatings absorb light with a wavelength above 370nm. Together, these achieve more than four orders suppression of long wave out-of-band light. A lowpass transmission filter with a position dependent cut-off wavelength is deposited on the last lens surface, directly in front of the detector. At the position where short wavelength light passes the filter, longer wavelength in-band stray light and ghosts are blocked. A simulation predicts that this graded filter reduces ghosting by a factor 20 and scatter related stray light by factor 30.

Paper Details

Date Published: 17 November 2017
PDF: 6 pages
Proc. SPIE 10563, International Conference on Space Optics — ICSO 2014, 105634R (17 November 2017); doi: 10.1117/12.2304065
Show Author Affiliations
Martijn Brouwer, TNO (Netherlands)
Robin van Buuren, TNO (Netherlands)
Niels Gawlitta, TNO (Netherlands)
Semen Grabarnik, ESTEC (Netherlands)
Nick van der Valk, TNO (Netherlands)
Rob Vink, TNO (Netherlands)
Hedser van Brug, TNO (Netherlands)
Huib Visser, TNO (Netherlands)

Published in SPIE Proceedings Vol. 10563:
International Conference on Space Optics — ICSO 2014
Zoran Sodnik; Bruno Cugny; Nikos Karafolas, Editor(s)

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