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arXiv · 2111.14751

Plastic Laminate Antireflective Coatings for Millimeter-wave Optics in BICEP Array

Marion Dierickx·P. A. R. Ade·Zeeshan Ahmed·Mandana Amiri·Denis Barkats·Ritoban Basu Thakur·Colin A. Bischoff·Dominic Beck·James J. Bock·Victor Buza·James R. Cheshire IV·Jake Connors·James Cornelison·Michael Crumrine·Ari Jozef Cukierman·Edward Denison·Lionel Duband·Miranda Eiben·Sofia Fatigoni·Jeff P. Filippini·Christos Giannakopoulos·Neil Goeckner-Wald·David Goldfinger·James A. Grayson·Paul Grimes·Grantland Hall·George Halal·Mark Halpern·Emma Hand·Sam A. Harrison·Shawn Henderson·Sergi Hildebrandt·Gene C. Hilton·Johannes Hubmayr·Howard Hui·Kent D. Irwin·Jae Hwan Kang·Kirit S. Karkare·Sinan Kefeli·J. M. Kovac·Chao-Lin Kuo·King Lau·Erik M. Leitch·Amber Lennox·K·. G. Megerian·Lorenzo Minutolo·Lorenzo Moncelsi·Yuka Nakato·Toshiya Namikawa·H. T. Nguyen·Roger O'brient·Steven Palladino·Matthew Petroff·Nathan Precup·Thomas Prouve·Clement Pryke·Benjamin Racine·Carl D. Reintsema·Destiny Santalucia·Alessandro Schillaci·Benjamin Schmitt·Baibhav Singari·Ahmed Soliman·Tyler St Germaine·Bryan Steinbach·Rashmi Sudiwala·Keith L. Thompson·Carole Tucker·Anthony D. Turner·Caterina Umiltà·Clara Verges·Abigail G. Vieregg·Albert Wandui·Alexis C. Weber·Don Wiebe·Justin Willmert·Wai Ling K. Wu·Hung-I Yang·Ki Won Yoon·Edward Young·Cyndia Yu·Lingzhen Zeng·Cheng Zhang·Silvia Zhang
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Abstract

The BICEP/Keck series of experiments target the Cosmic Microwave Background at degree-scale resolution from the South Pole. Over the next few years, the "Stage-3" BICEP Array (BA) telescope will improve the program's frequency coverage and sensitivity to primordial B-mode polarization by an order of magnitude. The first receiver in the array, BA1, began observing at 30/40 GHz in early 2020. The next two receivers, BA2 and BA3, are currently being assembled and will map the southern sky at frequencies ranging from 95 GHz to 150 GHz. Common to all BA receivers is a refractive, on-axis, cryogenic optical design that focuses microwave radiation onto a focal plane populated with antenna-coupled bolometers. High-performance antireflective coatings up to 760 mm in aperture are needed for each element in the optical chain, and must withstand repeated thermal cycles down to 4 K. Here we present the design and fabrication of the 30/40 GHz anti-reflection coatings for the recently deployed BA1 receiver, then discuss laboratory measurements of their reflectance. We review the lamination method for these single- and dual-layer plastic coatings with indices matched to various polyethylene, nylon and alumina optics. We also describe ongoing efforts to optimize coatings for the next BA cryostats, which may inform technological choices for future Small-Aperture Telescopes of the CMB "Stage 4" experiment.

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Marion Dierickx, P. A. R. Ade, Zeeshan Ahmed, Mandana Amiri, Denis Barkats, Ritoban Basu Thakur, Colin A. Bischoff, Dominic Beck, James J. Bock, Victor Buza, James R. Cheshire IV, Jake Connors, James Cornelison, Michael Crumrine, Ari Jozef Cukierman, Edward Denison, Lionel Duband, Miranda Eiben, Sofia Fatigoni, Jeff P. Filippini, Christos Giannakopoulos, Neil Goeckner-Wald, David Goldfinger, James A. Grayson, Paul Grimes, Grantland Hall, George Halal, Mark Halpern, Emma Hand, Sam A. Harrison, Shawn Henderson, Sergi Hildebrandt, Gene C. Hilton, Johannes Hubmayr, Howard Hui, Kent D. Irwin, Jae Hwan Kang, Kirit S. Karkare, Sinan Kefeli, J. M. Kovac, Chao-Lin Kuo, King Lau, Erik M. Leitch, Amber Lennox, K, . G. Megerian, Lorenzo Minutolo, Lorenzo Moncelsi, Yuka Nakato, Toshiya Namikawa, H. T. Nguyen, Roger O'brient, Steven Palladino, Matthew Petroff, Nathan Precup, Thomas Prouve, Clement Pryke, Benjamin Racine, Carl D. Reintsema, Destiny Santalucia, Alessandro Schillaci, Benjamin Schmitt, Baibhav Singari, Ahmed Soliman, Tyler St Germaine, Bryan Steinbach, Rashmi Sudiwala, Keith L. Thompson, Carole Tucker, Anthony D. Turner, Caterina Umiltà, Clara Verges, Abigail G. Vieregg, Albert Wandui, Alexis C. Weber, Don Wiebe, Justin Willmert, Wai Ling K. Wu, Hung-I Yang, Ki Won Yoon, Edward Young, Cyndia Yu, Lingzhen Zeng, Cheng Zhang, Silvia Zhang. 2021-11-29. Plastic Laminate Antireflective Coatings for Millimeter-wave Optics in BICEP Array. https://doi.org/10.1007/s10909-023-02967-1

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