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The Simons Observatory: metamaterial microwave absorber and its cryogenic applications
- Publication Year :
- 2021
- Publisher :
- country:US, 2021.
-
Abstract
- Controlling stray light at millimeter wavelengths requires special optical design and selection of absorptive materials that should be compatible with cryogenic operating environments. While a wide selection of absorptive materials exists, these typically exhibit high indices of refraction and reflect/scatter a significant fraction of light before absorption. For many lower index materials such as commercial microwave absorbers, their applications in cryogenic environments are challenging. In this paper, we present a new tool to control stray light: metamaterial microwave absorber tiles. These tiles comprise an outer metamaterial layer that approximates a lossy gradient index anti-reflection coating. They are fabricated via injection molding commercially available carbon-loaded polyurethane (25\% by mass). The injection molding technology enables mass production at low cost. The design of these tiles is presented, along with thermal tests to 1 K. Room temperature optical measurements verify their control of reflectance to less than 1\% up to 65$\circ$ angles of incidence, and control of wide angle scattering below 0.01\%. The dielectric properties of the bulk carbon-loaded material used in the tiles is also measured at different temperatures, confirming that the material maintains similar dielectric properties down to 3 K.<br />10 pages, 11 figures, published in Applied Optics, selected as "Editor's pick"
- Subjects :
- Materials science
FOS: Physical sciences
Physics::Optics
Dielectric
engineering.material
01 natural sciences
CMB, Cryogenics, polarization, metamaterial, telescope
010309 optics
FIS/05 - ASTRONOMIA E ASTROFISICA
Optics
Coating
0103 physical sciences
Electrical and Electronic Engineering
Absorption (electromagnetic radiation)
Engineering (miscellaneous)
Instrumentation and Methods for Astrophysics (astro-ph.IM)
Stray light
business.industry
Metamaterial
Refraction
Atomic and Molecular Physics, and Optics
Molding (decorative)
engineering
business
Astrophysics - Instrumentation and Methods for Astrophysics
Microwave
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....fbaade6cf29cc189dce785587d9f12e4