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arXiv · 2303.10273

Broadband plasma spray anti-reflection coating technology for millimeter-wave astrophysics

Oliver Jeong·Richard Plambeck·Christopher Raum·Aritoki Suzuki·Adrian T. Lee
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Abstract

We present a broadband plasma spray anti-reflection (AR) coating technology for millimeter-wave astrophysics experiments with large-format, cryogenic optics. By plasma spraying alumina- and silica-based powders, we have produced coatings of tunable index of refraction and thickness, low loss, and coefficient of thermal expansion matched to alumina substrates. We demonstrate two-layer AR coatings on alumina with reflection below 5% over 82% and 69% fractional bandwidths for 90/150 and 220/280 GHz passband designs, respectively, and band-averaged absorption loss reduced to ~1% at 100 K for both AR coatings. We describe the design, tolerance, fabrication process, and optical measurements of these AR coatings.

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Oliver Jeong, Richard Plambeck, Christopher Raum, Aritoki Suzuki, Adrian T. Lee. 2023-03-17. Broadband plasma spray anti-reflection coating technology for millimeter-wave astrophysics. https://doi.org/10.1364/ao.478048

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