Design, Fabrication, and Analysis of High-Performance UV Band-pass filters

NASA’s strategic mission concept, ATLAST (Advanced Technology Large-Aperture Space Telescope), is a telescope merging ultraviolet (UV) astrophysics and visible exoplanet science. We propose to investigate high-performance visible blind UV band-pass filter coatings with high transmission in the Far-Ultra Violet (FUV) spectral range for the instrument's detector technology. The coating performance will be evaluated both theoretically and experimentally in the context of meeting requirements for exoplanet research.

High-performance mirror coatings were identified as one of five key technology development priorities in the ATLAST Science, Mission, and Technology Roadmap.  One of the challenges of merging UV astrophysics with visible-wavelength exoplanet science is to design a multilayer coating which provides high transmittance in the UV spectrum while eliminating the visible.  ATLAST requires coatings that have a high reflectivity over a broad bandwidth; therefore, it is crucial the detector has high sensitivity in the FUV while blocking the visible so the appropriate science at each spectral bandwidth can be conducted. The scope of this work involves determining the best combination of materials that have minimal hygroscopic properties for a dielectric FUV multilayer band-pass filter design. By using materials with low absorption in this spectral range, detector sensitivity and the detectable redshift range will be enhanced. Coupling enhanced FUV coated optics with this detector technology will be game changing as it will yield more sensitive instruments and more design freedoms in an optical system.