摘要： We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2). 其他題名： Appl Opt 出版者： United States 出版日期： 2016-12-01 出處： Applied Optics, 2016-12, Vol.55 (34), p.D22-D28 資源來源： Optical Society Journals 識別號： ISSN: 1559-128X 識別號： EISSN: 2155-3165 識別號： EISSN: 1539-4522 識別號： DOI: 10.1364/AO.55.000D22 識別號： PMID: 27958435
