Title
Optical coatings for the Tropomi UV channel
Author
Brouwer, E.A.M.
van Buuren, R.A.
Gawlitta, N.
Grabarnik, S.
van der Valk, N.C.J.
Vink, H.J.P.
van Brug, H.
Visser, H.
Contributor
Sodnik, Z. (editor)
Cugny, B. (editor)
Karafolas, N. (editor)
Publication year
2017
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.
Subject
2014 Mechanics, Materials and Structures
IM - Instrument Manufacturing
TS - Technical Sciences
High Tech Systems & Materials
Electronics
Industrial Innovation
Black coatings
Optical coatings
Stray light
Cutoff wavelengths
Earth irradiances
Earth observations
Mirror coating
Position dependents
Short wavelengths
Shorter wavelength
Transmission filters
Light transmission
To reference this document use:
http://resolver.tudelft.nl/uuid:e2ad4e2b-5e80-45f4-b5ce-2d295e9c4852
TNO identifier
842175
Publisher
SPIE
ISBN
9781510616158
ISSN
0277-786X
Source
International Conference on Space Optics, ICSO 2014, 7-10 October 2014, La Caleta, Tenerife, Canary Islands, Spain, 10563
Series
Proceedings of SPIE - The International Society for Optical Engineering
Article number
105634R
Document type
conference paper