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2021 年度 実施状況報告書

Novel Method to Measure the Gravitational Constant

研究課題

研究課題/領域番号 21K03603
研究機関立教大学

研究代表者

Zeidler Simon  立教大学, 理学部, 助教 (80773598)

研究期間 (年度) 2021-04-01 – 2023-03-31
キーワードInterferometer / Mach-Zehnder / Laser
研究実績の概要

During this fiscal year, I have used the dedicated Kiban-C budget to purchase optics to set up a polarization interferometer which I have used to study the polarization stability of the frequency-stabilized laser, which has been purchased as well as one of the core elements of my project. I could show that the laser is polarization stable down to mrad which was one of the key-features to be shown.
In addition, a Mach-Zehnder Interferometer has been build and tested in form of a heterodyne detector for weak oscillations of a test-mirror connected to a Piezo-osillator. With this setup and by using a HeNe-laser (different to the frequency-stabilized one), I could show its effectivity as a Doppler-Interferometer by detecting oscillation amplitudes of ~70pm.
I have done comprehensive simulation on the effects of gravity on a laser and concluded slight changes in my future research plan. Instead of a microlense-array, a frequency-modulated laser shall be used as input-field for the cavities. With such an input, the reflecting and interfering fields can be treated as Doppler-shifted and detected with the above mentioned heterodyne detector.

現在までの達成度 (区分)
現在までの達成度 (区分)

2: おおむね順調に進展している

理由

Within the set schedule, I could purchase all necessary parts and perform the initial setups and measurements as planned. In addition, I could reconsider the setup to become more effective for the measurements to come.

今後の研究の推進方策

As mentioned in the report, the original plan will slightly change from a Michelson Interferometer (IF) with microlense-array towards a Michelson IF with frequency-modulated laser (FML) and heterodyne detector. This scheme has several benefits: 1) polarization stable, as optics like lenses tend to change polarization depending on material and stress. 2) increased sensitivity due to frequency-modulation which is immune against amplitude noise.
As a consequence, the schedule will be adjusted as follows. Within the next fiscal year, the Michelson IF (without Fabry-Perot cavities) will be build and adjusted to work with a FML which is realized by using the frequency-stabilized laser purchased in 2021 and an electro-optical modulator (EOM). The second milestone during 2022 is then to connect this IF setup with the heterodyne detector constructed in 2021.
In parallel, a journal paper is prepared to summarize the considerations and give first impressions on the sensitivity of the instrument.

次年度使用額が生じた理由

Use incurring amount as follows together with the budget for next year.
As written in the research plan for the next FY, a Michelson IF with FML is to be build. For this setup, dielectric high-reflectivity mirrors for the MIchelson IF are needed in addition to optics for using the frequency-stabilized laser as input source.
In order to modulate this laser into a FML, an electro-optical modulator (EOM) plus amplifier equipment is needed which will use most of the funds for the next FY (expected: ~800.000\). Together with the auxiliary optical and mechanical components (lenses, holders, posts, etc.), 1.400.000\ are expected to be used up fully.

  • 研究成果

    (1件)

すべて 2021

すべて 学会発表 (1件) (うち国際学会 1件)

  • [学会発表] Novel Method to Measure Gravity at small Distances2021

    • 著者名/発表者名
      Simon Zeidler
    • 学会等名
      JPS autumn meeting 2021
    • 国際学会

URL: 

公開日: 2022-12-28  

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