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Proceedings Paper

Enhanced far-ultraviolet reflectance of MgF2 and LiF over-coated Al mirrors
Author(s): Manuel A. Quijada; Javier Del Hoyo; Stephen Rice
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Paper Abstract

This paper presents and discuss data obtained on a distribution of Al+MgF2 and Al+LiF witness coupons that show substantial gains in reflectance in the far-ultraviolet (FUV) part of the optical spectrum (90−180 nm). These samples, which have dimensions of 2×2 inches, were coated at various locations inside a 2−me diameter coating chamber at the Goddard Space Flight Center in Greenbelt, MD (USA). These experiments were done to demonstrate a scale−up process for coating up to a 1−m diameter optic, and hence realize the gain in throughput that could be obtained for a telescope system that would employ such mirror coatings. These coatings have been optimized for Lyman-alpha (121.6 nm) or lower wavelengths and they are prepared with the deposition of the MgF2 or LiF layers done at elevated (∼ 250 °C) temperature. These results will be compared to ambient or “cold” depositions. We will also present optical characterization of little-studied rare-earth fluorides, such as GdF3 and LuF3, that exhibit low absorption over a broad wavelength range and could therefore be used as high-index materials to produce dielectric coatings at FUV wavelengths.

Paper Details

Date Published: 24 July 2014
PDF: 10 pages
Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91444G (24 July 2014); doi: 10.1117/12.2057438
Show Author Affiliations
Manuel A. Quijada, NASA Goddard Space Flight Ctr. (United States)
Javier Del Hoyo, NASA Goddard Space Flight Ctr. (United States)
Stephen Rice, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 9144:
Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray
Tadayuki Takahashi; Jan-Willem A. den Herder; Mark Bautz, Editor(s)

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