| Project/Area Number |
19K03897
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
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| Research Institution | National Astronomical Observatory of Japan |
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Principal Investigator |
Flaminio Raffaele 国立天文台, 重力波プロジェクト, 特別客員研究員 (10723108)
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| Co-Investigator(Kenkyū-buntansha) |
LEONARDI MATTEO 国立天文台, 重力波プロジェクト, 助教 (90816448)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2021: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | gravitational wave / mirror / crystal / coating / thermal noise / optical coating / crystals |
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| Outline of Research at the Start |
The first detections of gravitational waves from binary black holes mergers and binary neutron stars merger marked the beginning of gravitational wave astronomy. The sensitivity of these detectors is limited by thermal noise in the mirrors coatings. Recently crystalline coatings have been proposed as a solution to reduce the mirror thermal noise. In this research we propose to develop crystalline coatings with minimized thermo-optic noise. The coatings will be characterized to investigate its optical performances and to measure its thermal noise by means of a high finesse cavity.
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| Outline of Final Research Achievements |
The thermal noise of the mirrors used for the detection of gravitational waves is one of the main limitation to the detector's sensitivity. In this research we investigated mirrors based on GaAs/AlGaAs multi-layers coatings (called AlGaAs mirrors). We evaluated, for the first time, the effect of the thermo-optic noise in mirrors used with small laser beams as the ones used in table-top short optical cavities for the direct measurement of mirror thermal noise. In parallel, we characterized the optical performances of a 2.5 cm diameter AlGaAs mirrors optimized so to minimize its thermo-optic noise. We measured its scattering, its roughness and its point defects. Finally we realized AlGaAs mirrors with 10 cm diameter and we measured their optical performances.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は、その結果に基づき重力波検出器の感度の向上を図ることができるため、重力波天文学に有用である。さらに、オプトメカニカル研究、レーザー周波数安定化、光時計、垂直外部共振器面発光レーザー、ジャイロレーザーなど、他の科学技術分野への応用も期待される。
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