• France, Kevin
• Nikzad, Shouleh
• Jewell, April D.
• Hennessy, John
• Moore, Christopher S.

Abstract

Astronomical observations in the Lyman-ultraviolet (91 - 122 nm) are limited in part by the performance of reflective coatings. Currently, the best reflective mirror options for the UV wavelength range of 90 -122 nm are LiF+Al (R ~ 60% from 102 - 200 nm) and SiC (R ~ 30 % from 90 - 200 nm). Higher reflectivity coatings in the 90 - 122 nm range will improve sensitivity and allow for more complex instrumentation. We are working to develop, laboratory test and eventually space test new reflective UV coatings (R &gt; 70% from 90 - 115 nm) that also preserve high-reflectivity performance (R &gt; 80% from 115 - 800 nm) throughout the longer-wavelength vacuum ultraviolet and visible spectral bands. We present a progress report on our work with new protective thin film deposition techniques of metal fluorides (MgF<SUB>2</SUB> and AlF<SUB>3</SUB>) on high intrinsic broadband reflective metal (aluminum) surfaces. We present first test results from both traditional and atomic layer deposition processes. In this paper, we discuss the current status of the deposition process, coating substrates, reflectivity measurements for optical through far-ultraviolet wavelengths as well as environmental storage sensitivities....

Topics

• surface
• thin film
• aluminium
• atomic layer deposition