Patents by Inventor Shigeyoshi GOKA
Shigeyoshi GOKA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10720745Abstract: The present invention provides an atomic oscillator comprising: a first frequency synthesizer for multiplying a reference frequency signal oscillated with a first voltage control oscillator by a first multiplication ratio and synthesizing a first high frequency signal; a first semiconductor laser for emitting a first laser light modulated by the first high frequency signal; a second frequency synthesizer for multiplying an output signal oscillated by a second voltage control oscillator with a second multiplication ratio and synthesizing a second high frequency signal; a second semiconductor laser for emitting a second laser modulated by the second high frequency signal; a gas cell being emitted with the first laser light and the second laser light simultaneously, the gas cell enclosing a first alkali-metal atom gas, a second alkali-metal atom gas, and buffer gas; and a computer for setting the first multiplication ratio in the first frequency synthesizer.Type: GrantFiled: August 29, 2017Date of Patent: July 21, 2020Assignee: Tokyo Metropolitan UniversityInventor: Shigeyoshi Goka
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Publication number: 20190245315Abstract: [Problem to be Solved] To provide a gas-cell type atomic oscillator maintaining high frequency stability for a long period.Type: ApplicationFiled: August 29, 2017Publication date: August 8, 2019Inventor: Shigeyoshi GOKA
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Patent number: 9954544Abstract: A method for generating a CPT resonance, includes applying an electric current to a laser light-emitting element, to emit laser light having at least two wavelengths. The value of a direct current component of the electric current applied to the laser light-emitting element in a first period is greater than an oscillation threshold for the laser light-emitting element, and the value of the direct current component of the electric current applied to the laser light-emitting element in a second period, following the first period, is less than the value of the direct current component of the electric current in the first period. An alkali metal atom is irradiated with the laser light, the laser light generated in the first period and the laser light generated in the second period entering the alkali metal atom repeatedly a plurality of times to generate a Ramsey resonance.Type: GrantFiled: March 9, 2016Date of Patent: April 24, 2018Assignees: RICOH COMPANY, LTD., TOKYO METROPOLITAN UNIVERSITYInventors: Shigeyoshi Goka, Yuichiro Yano, Takumi Ide
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Patent number: 9917592Abstract: An atomic oscillator includes an alkali metal cell encapsulating an alkali metal atom; a light source that emits laser light; a light detector that detects light which has passed through the alkali metal cell; and a polarizer arranged between the alkali metal cell and the light detector. A modulation frequency in the light source is controlled, according to a coherent population trapping resonance which is a light absorption characteristic of a quantum interference effect for two kinds of resonant lights, by modulating the light source to generate sidebands and injecting laser lights with the sidebands into the alkali metal cell. A magnetic field is applied on the alkali metal cell in a direction parallel to a propagating direction of the laser light, and the laser light entering the alkali metal cell has a linear polarization, which is not parallel to a polarization direction of the polarizer.Type: GrantFiled: August 4, 2015Date of Patent: March 13, 2018Assignees: RICOH COMPANY, LTD., Tokyo Metropolitan University, Municipal University Corp.Inventors: Yuichiro Yano, Shigeyoshi Goka
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Publication number: 20160269037Abstract: A method for generating a CPT resonance, includes applying an electric current to a laser light-emitting element, to emit laser light having at least two wavelengths. The value of a direct current component of the electric current applied to the laser light-emitting element in a first period is greater than an oscillation threshold for the laser light-emitting element, and the value of the direct current component of the electric current applied to the laser light-emitting element in a second period, following the first period, is less than the value of the direct current component of the electric current in the first period. An alkali metal atom is irradiated with the laser light, the laser light generated in the first period and the laser light generated in the second period entering the alkali metal atom repeatedly a plurality of times to generate a Ramsey resonance.Type: ApplicationFiled: March 9, 2016Publication date: September 15, 2016Applicants: RICOH COMPANY, LTD., Tokyo Metropolitan UniversityInventors: Shigeyoshi GOKA, Yuichiro YANO, Takumi IDE
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Patent number: 9444476Abstract: An atomic oscillator includes an alkali-metal cell in which alkali-metal atoms are enclosed, a light source which irradiates the atoms in the alkali-metal cell with laser beams, a photodetector which detects a light amount of the laser beams passing through the alkali-metal cell to enter the photodetector, and a controller which generates sidebands including a pair of laser beams with different wavelengths by performing frequency modulation of a carrier on the light source, causes the pair of laser beams with the different wavelengths to enter the alkali-metal cell, and controls a modulation frequency according to optical absorption characteristics of the atoms by quantum interference effects of a pair of resonance laser beams, wherein the side bands include second-order or higher-order sidebands.Type: GrantFiled: August 28, 2013Date of Patent: September 13, 2016Assignees: RICOH COMPANY, LTD., Tokyo Metropolitan UniversityInventors: Shigeyoshi Goka, Yuichiro Yano
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Publication number: 20150338476Abstract: An atomic oscillator includes an alkali metal cell encapsulating an alkali metal atom; a light source that emits laser light; a light detector that detects light which has passed through the alkali metal cell; and a polarizer arranged between the alkali metal cell and the light detector. A modulation frequency in the light source is controlled, according to a coherent population trapping resonance which is a light absorption characteristic of a quantum interference effect for two kinds of resonant lights, by modulating the light source to generate sidebands and injecting laser lights with the sidebands into the alkali metal cell. A magnetic field is applied on the alkali metal cell in a direction parallel to a propagating direction of the laser light, and the laser light entering the alkali metal cell has a linear polarization, which is not parallel to a polarization direction of the polarizer.Type: ApplicationFiled: August 4, 2015Publication date: November 26, 2015Applicants: RICOH COMPANY, LTD., Tokyo Metropolitan University, Municipal University Corp.Inventors: Yuichiro Yano, Shigeyoshi Goka
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Patent number: 9136851Abstract: An atomic oscillator includes an alkali metal cell encapsulating an alkali metal atom; a light source that emits laser light; a light detector that detects light which has passed through the alkali metal cell; and a polarizer arranged between the alkali metal cell and the light detector. A modulation frequency in the light source is controlled, according to a coherent population trapping resonance which is a light absorption characteristic of a quantum interference effect for two kinds of resonant lights, by modulating the light source to generate sidebands and injecting laser lights with the sidebands into the alkali metal cell. A magnetic field is applied on the alkali metal cell in a direction parallel to a propagating direction of the laser light, and the laser light entering the alkali metal cell has a linear polarization, which is not parallel to a polarization direction of the polarizer.Type: GrantFiled: February 10, 2014Date of Patent: September 15, 2015Assignees: RICOH COMPANY, LTD., Tokyo Metropolitan University, Municipal University Corp.Inventors: Yuichiro Yano, Shigeyoshi Goka
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Publication number: 20150222285Abstract: An atomic oscillator includes an alkali-metal cell in which alkali-metal atoms are enclosed, a light source which irradiates the atoms in the alkali-metal cell with laser beams, a photodetector which detects a light amount of the laser beams passing through the alkali-metal cell to enter the photodetector, and a controller which generates sidebands including a pair of laser beams with different wavelengths by performing frequency modulation of a carrier on the light source, causes the pair of laser beams with the different wavelengths to enter the alkali-metal cell, and controls a modulation frequency according to optical absorption characteristics of the atoms by quantum interference effects of a pair of resonance laser beams, wherein the side bands include second-order or higher-order sidebands.Type: ApplicationFiled: August 28, 2013Publication date: August 6, 2015Applicants: RICOH COMPANY, LTD., Tokyo Metropolitan UniversityInventors: Shigeyoshi Goka, Yuichiro Yano
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Publication number: 20140225678Abstract: An atomic oscillator includes an alkali metal cell encapsulating an alkali metal atom; a light source that emits laser light; a light detector that detects light which has passed through the alkali metal cell; and a polarizer arranged between the alkali metal cell and the light detector. A modulation frequency in the light source is controlled, according to a coherent population trapping resonance which is a light absorption characteristic of a quantum interference effect for two kinds of resonant lights, by modulating the light source to generate sidebands and injecting laser lights with the sidebands into the alkali metal cell. A magnetic field is applied on the alkali metal cell in a direction parallel to a propagating direction of the laser light, and the laser light entering the alkali metal cell has a linear polarization, which is not parallel to a polarization direction of the polarizer.Type: ApplicationFiled: February 10, 2014Publication date: August 14, 2014Applicants: TOKYO METROPOLITAN UNIVERSITY, MUNICIPAL UNIVERSITY CORP., RICOH COMPANY, LTD.Inventors: Yuichiro YANO, Shigeyoshi GOKA