Lyons, Matthew, Hargrave, Peter  ORCID: https://orcid.org/0000-0002-3109-6629, Veenendaal, Ian, Sudiwala, Rashmikant ORCID: https://orcid.org/0000-0003-3240-5304, Braithewaite, Lottie, Savini, Giorgio, Shitvov, Alexey, Zhang, Jin and Gudmundsson, Jon E.
2026.
End-to-end precision characterisation of broadband antireflection-coated mm-wave components.
Presented at: SPIE Astronomical Telescopes + Instrumentation, 2026,
Copenhagen, Denmark,
5-10 July 2026.
Published in: Coyle, Laura E., Perrin, Marshall D. and Matsuura, Shuji eds.
Proceedings of SPIE:Space Telescopes and Instrumentation 2026: Optical, Infrared, and Millimeter Wave.
, vol.14145
SPIE,
p. 276.
10.1117/12.3102809
|
Abstract
Future sub-millimetre optical systems require low-loss, low-reflectance, broadband anti-reflection (AR) coatings, for which interspersed polymer layers with matched refractive indices are a proven option. However, hot-press bonding can change refractive index and deform the optic substrate, degrading lens performance. We address this by annealing the substrate before machining, relieving internal stresses and stabilizing optical properties so the AR-coating process does not distort the lens. We investigate cast polypropylene (CPP) and porous PTFE (pPTFE) as coating materials for UHMWPE optics and identify an optimal annealing cycle enabling reliable fabrication and characterization. Using spectroscopy and an MCMC-based transfer-matrix model, we extract refractive index and loss from 60–900 GHz. These measurements inform optimized 3- and 5-layer AR-coating designs validated on 70 mm pucks and demonstrated on a full-size two-lens system operating over 166–448 GHz.
| Item Type: | Conference or Workshop Item - published (Poster) |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Schools > Physics and Astronomy |
| Publisher: | SPIE |
| Last Modified: | 05 Aug 2026 02:43 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/188221 |
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