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    SOUND MEASUREMENT APPARATUS, SOUND MEASUREMENT METHOD, AND PROGRAM
    1.
    发明申请
    SOUND MEASUREMENT APPARATUS, SOUND MEASUREMENT METHOD, AND PROGRAM 有权

    公开(公告)号：US20240410741A1

    公开(公告)日：2024-12-12

    申请号：US18702396

    申请日：2021-10-28

    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

    Inventor： Kenji ISHIKAWA ,  Yoshifumi SHIRAKI ,  Takehiro MORIYA ,  Atsushi ISHIZAWA ,  Kenichi HITACHI ,  Katsuya OGURI

    IPC: G01H9/00

    Abstract: Provided is a measurement technology of an optical phase modulation amount due to sound without being affected by noise included in average light intensity. The measurement technology includes: an interference light generator that obtains first light including light subjected to optical phase modulation by a sound measurement unit and second light different from the first light and including light subjected to optical phase modulation by the sound measurement unit from light emitted from a light source; a first photodetector that obtains a first electrical signal from the first light; a second photodetector that obtains a second electrical signal from the second light; a differential signal generator that obtains a differential signal that is a difference between the first electrical signal and the second electrical signal; and an optical phase modulation amount adjuster that adjusts an optical phase modulation amount φ0 due to an element other than sound by fixing an interferometer such that a phase of an interference fringe is in mid-fringe by using the differential signal as an error signal, in which the optical phase modulation amount φs due to sound is measured as a current Δi of the differential signal, and the first photodetector and the second photodetector are adjusted such that output voltages are saturated when light that causes a phase fluctuation exceeding a predetermined range around mid-fringe is input.

    MAGNETO-OPTICAL TRAP METHOD AND APPARATUS
    2.
    发明申请
    MAGNETO-OPTICAL TRAP METHOD AND APPARATUS 审中-公开

    公开(公告)号：US20200275547A1

    公开(公告)日：2020-08-27

    申请号：US16799626

    申请日：2020-02-24

    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION ,  RIKEN

    Inventor： Hiromitsu IMAI ,  Tomoyo AKATSUKA ,  Katsuya OGURI ,  Atsushi ISHIZAWA ,  Hideki GOTOH ,  Hidetoshi KATORI ,  Masao TAKAMOTO

    IPC: H05H3/02 ,  G21K1/093

    Abstract: A magneto-optical trap apparatus includes a vacuum vessel for encapsulating an atom to be trapped, an anti-Helmholtz coil for applying a magnetic field to an inside of the vacuum vessel, a laser device for generating a laser beam, and an irradiation device for irradiating the generated laser beam from a plurality of directions. The laser beam includes a first laser beam detuned from a first resonance frequency when the atom transits from a total angular momentum quantum number F in a ground state to a total angular momentum quantum number F′=F+1 in an excited state, and a second laser beam detuned from a second resonance frequency when the atom transits from the total angular momentum quantum number F in the ground state to a total angular momentum quantum number F′=F−1 in the excited state, among transitions from J=0 in a ground state to J′=1 in an excited state.

    SOUND MEASUREMENT METHOD
    4.
    发明公开
    SOUND MEASUREMENT METHOD 审中-公开

    公开(公告)号：US20230288247A1

    公开(公告)日：2023-09-14

    申请号：US18017025

    申请日：2020-07-28

    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

    Inventor： Kenji ISHIKAWA ,  Yoshifumi SHIRAKI ,  Takehiro MORIYA ,  Kenichi HITACHI ,  Atsushi ISHIZAWA ,  Katsuya OGURI

    IPC: G01H9/00 ,  G01B9/02001 ,  H04R23/00

    CPC classification number: G01H9/00 ,  G01B9/0201 ,  H04R23/008

    Abstract: An optical phase modulation amount measurement technology using sound without being affected by noise included in an average light intensity is provided. A sound measurement method includes an interference light generation step of obtaining first light including light subjected to light phase modulation by a sound measurement unit and second light including light subjected to light phase modulation by the sound measurement unit, which differs from the first light, from light emitted from a light source, a first light detection step of obtaining a first electrical signal from the first light, a second light detection step of obtaining a second electrical signal from the second light, and a differential signal generation step of obtaining a differential signal that is a difference between the first electrical signal and the second electrical signal, wherein a phase of the light subjected to light phase modulation included in the first light and a phase of the light subjected to the light phase modulation included in the second light are in an inverted relationship, and an optical phase modulation amount φs by sound is measured as a current Δi of the differential signal expressed by an equation Δi=βIA cos (φs+φ0) (where β is a predetermined constant, IA is an amplitude of an interference fringe, and φ0 is an optical phase modulation amount by an element other than sound).

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