Development of cryogenically cooled broadband polarization modualtor to probe the inflationary universe

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05441
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Astronomy
• Research Institution: The University of Tokyo (2016-2017); Japan Aerospace EXploration Agency (2015)
• Principal Investigator: Matsumura Tomotake 東京大学, カブリ数物連携宇宙研究機構, 特任准教授 (70625003)
• Research Collaborator: KATAYAMA Nobuhiko 東京大学, カブリ数物連携宇宙研究機構, 教授 (50290854) ; SAKURAI Yuki 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (50780847) ; OHSAKI Hiroyuki 東京大学, 大学院新領域創成科学研究科, 教授 (10203754)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: インフレーション / 宇宙マイクロ波背景放射 / 偏光観測 / 応用超電導 / 超電導磁気軸受 / レーザー加工

Outline of Final Research Achievements

The theory of inflation is testable by using the measurement of the cosmic microwave background (CMB) polarization. The expected sensitivity for a next-generation CMB polarization experiment is to probe the nano-Kelvin fluctuation. The experimental challenge comes when one has to make a distinction between the signal and the instrumentally induced fluctuation. In order to overcome this challenge, we develop a polarization modulator using a cryogenically cooled continuously rotating broadband half-wave plate. We achieve a broadband anti-reflection by a moth-eye structure and also we build a rotational mechanism using a superconducting magnetic bearing. We characterize its thermal, optical, and kinematic performances experimentally, and demonstrate the applicability of such this system for a next-generation CMB polarization experiment.

Free Research Field

観測的宇宙論