Demonstration of anti-reflective structures over a large area for CMB polarization experiments

Ryota Takaku, Shaul Hanany, Yurika Hoshino, Hiroaki Imada, Hirokazu Ishino, Nobuhiko Katayama, Kunimoto Komatsu, Kuniaki Konishi, Makoto Kuwata Gonokami, Tomotake Matsumura, Kazuhisa Mitsuda, Haruyuki Sakurai, Yuki Sakurai, Qi Wen, Noriko Y. Yamasaki, Karl Young, Junji Yumoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Sapphire, alumina, and silicon present the following characteristics that make them suitable as optical elements for millimeter and sub-millimeter applications: low-loss, high thermal conductivity at cryogenic temperatures, and high refractive index ∼3. However, the high index also leads to high reflection. We developed a technique to machine sub-wavelength structures (SWS) as a broadband anti-reflection coating on these materials through laser ablation. We describe here the status of our development: Transmission measurements of fabricated samples in a diameter of 34.5 mm agree with predictions, and we are now focusing on increasing the fabrication area with high processing rate. This is motivated by the need of ∼500 mm diameter optical elements for the next-generation cosmic microwave background polarization experiments. We show our large area machining method on the alumina and sapphire over an area of < 5200 mm2with the processing rate of < 4:0 mm3=min:, and the transmission measurements are consistent with the predictions.

Original languageEnglish
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X
EditorsJonas Zmuidzinas, Jian-Rong Gao
PublisherSPIE
ISBN (Electronic)9781510636934
DOIs
Publication statusPublished - 2020
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X 2020 - Virtual, Online, United States
Duration: Dec 14 2020Dec 22 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume11453
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X 2020
CountryUnited States
CityVirtual, Online
Period12/14/2012/22/20

Keywords

  • CMB
  • broadband anti-reection
  • laser ablation
  • millimeter-wavelength

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Demonstration of anti-reflective structures over a large area for CMB polarization experiments'. Together they form a unique fingerprint.

Cite this