Patents by Inventor Yasukazu Izawa

Yasukazu Izawa 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).

  • Patent number: 9325149
    Abstract: A multi-beam combining apparatus includes a phase shifting section, a superposing section, an observing section and a phase control section. The phase shifting section generates a plurality of phase-shifted laser beams by shifting the phase of each of the plurality of laser beams. The superposing section generates a plurality of superposed laser beam by superposing the reference laser beam and each of the plurality of phase-shifted laser beams. The observing section generates interference pattern data of a spatial interference pattern which appears when observing each of the superposed laser beams. The phase control section carries out a feedback control of the phase shifts in the phase shifting section based on the interference pattern data obtained for every superposed laser beam, and thereby sets the plurality of phase-shifted laser beams to desired states.
    Type: Grant
    Filed: January 17, 2013
    Date of Patent: April 26, 2016
    Assignees: Mitsubishi Heavy Industries, Ltd., Institute for Laser Technology, Osaka University
    Inventors: Koichi Hamamoto, Takahiro Yamada, Haik Chosrowjan, Hiroaki Furuse, Masayuki Fujita, Yasukazu Izawa, Junji Kawanaka, Noriaki Miyanaga
  • Publication number: 20150138618
    Abstract: A multi-beam combining apparatus includes a phase shifting section, a superposing section, an observing section and a phase control section. The phase shifting section generates a plurality of phase-shifted laser beams by shifting the phase of each of the plurality of laser beams. The superposing section generates a plurality of superposed laser beam by superposing the reference laser beam and each of the plurality of phase-shifted laser beams. The observing section generates interference pattern data of a spatial interference pattern which appears when observing each of the superposed laser beams. The phase control section carries out a feedback control of the phase shifts in the phase shifting section based on the interference pattern data obtained for every superposed laser beam, and thereby sets the plurality of phase-shifted laser beams to desired states.
    Type: Application
    Filed: January 17, 2013
    Publication date: May 21, 2015
    Applicants: Mitsubishi Heavy Industries, Ltd., Institute for Laser Technology, OSAKA UNIVERSITY
    Inventors: Koichi Hamamoto, Takahiro Yamada, Haik Chosrowjan, Hiroaki Furuse, Masayuki Fujita, Yasukazu Izawa, Junji Kawanaka, Noriaki Miyanaga
  • Patent number: 7885387
    Abstract: The present invention is made to provide an extreme ultraviolet light source target or an X-ray source target having a good operationality. An extreme ultraviolet light source target in accordance with an aspect of the present invention is obtained by including a heavy metal such as tin into a matrix made of a polymeric material such as hydroxylpropylcellulose (HPC). The target can be manufactured by mixing the heavy metal and the polymeric material with a solvent, and evaporating the solvent. Since the target uses the polymeric material as a matrix, the target can be easily deformed to have a desired shape. For this reason, the target can be easily attached to a target holder irrespective of the shape of the holder, resulting in a good operationality of the target. Furthermore, an emission efficiency can be improved by including the heavy metal at a low density.
    Type: Grant
    Filed: August 29, 2005
    Date of Patent: February 8, 2011
    Assignee: Osaka University
    Inventors: Keiji Nagai, Qincui Gu, Takayoshi Norimatsu, Shinsuke Fujioka, Hiroaki Nishimura, Katsunobu Nishihara, Noriaki Miyanaga, Yasukazu Izawa
  • Patent number: 7653100
    Abstract: The present invention relates to a solid-state laser module, and so on, having a structure for enabling optical output of high quality to be obtained. The solid-state laser module includes a vacuum container with windows, and a heat sink, a solid-state laser medium, and a pair of transparent members are housed in the vacuum container in an integrally assembled state. The solid-state laser medium and the pair of transparent members respectively have disk shapes, and the pair of transparent members sandwich the solid-state laser medium. The thermal conductivity of each of the pair of transparent members is higher than the thermal conductivity of the solid-state laser medium.
    Type: Grant
    Filed: November 24, 2005
    Date of Patent: January 26, 2010
    Assignees: Osaka University, Hamamatsu Photonics K.K.
    Inventors: Yasukazu Izawa, Masayuki Fujita, Shigeki Tokita, Tadashi Ikegawa, Toshiyuki Kawashima, Hirofumi Kan
  • Patent number: 7521702
    Abstract: An object of the present invention is to provide an extreme ultraviolet light source target which can emits extreme ultraviolet light with high emission efficiency. A solid target made of heavy metal or heavy-metal compound and having a density 0.5 to 80% that of the crystal density is used. When the target is irradiated with a laser beam, plasma of the heavy metal contained in the target is generated, and extreme ultraviolet light having a predetermined wavelength which corresponds to the kind of the heavy metal is emitted from the plasma. When the density of the target is made to be smaller than the crystal density as described above, space distribution of the density of the generated plasma can be controlled, and the region in which plasma absorbs energy of the laser beam overlaps the region in which the plasma emits the extreme ultraviolet light. Thus, emission efficiency can be improved, preventing energy loss.
    Type: Grant
    Filed: December 26, 2003
    Date of Patent: April 21, 2009
    Assignee: Osaka University
    Inventors: Keiji Nagai, Hiroaki Nishimura, Takayoshi Norimatsu, Katsunobu Nishihara, Noriaki Miyanaga, Masahiro Nakatsuka, Yasukazu Izawa, Tatsuhiko Yamanaka, Mitsuo Nakai, Keisuke Shigemori, Masakatsu Murakami, Yoshinori Shimada, Shigeaki Uchida, Hiroyuki Furukawa, Atsushi Sunahara, Vasilli Zhakhovski, Ryouji Matsui, Takahiro Hibino, Tomoharu Okuno
  • Publication number: 20080157011
    Abstract: The present invention is made to provide an extreme ultraviolet light source target or an X-ray source target having a good operationality. An extreme ultraviolet light source target in accordance with an aspect of the present invention is obtained by including a heavy metal such as tin into a matrix made of a polymeric material such as hydroxylpropylcellulose (HPC). The target can be manufactured by mixing the heavy metal and the polymeric material with a solvent, and evaporating the solvent. Since the target uses the polymeric material as a matrix, the target can be easily deformed to have a desired shape. For this reason, the target can be easily attached to a target holder irrespective of the shape of the holder, resulting in a good operationality of the target. Furthermore, an emission efficiency can be improved by including the heavy metal at a low density.
    Type: Application
    Filed: August 29, 2005
    Publication date: July 3, 2008
    Applicant: OSAKA UNIVERSITY
    Inventors: Keiji Nagai, Qincui Gu, Takayoshi Norimatsu, Shinsuke Fujioka, Hiroaki Nishimura, Katsunobu Nishihara, Noriaki Miyanaga, Yasukazu Izawa
  • Publication number: 20080089372
    Abstract: A solid laser module etc. having a structure that enables to obtain a high-quality light output. The solid laser module has a vacuum container with a window, and a heat sink, a solid laser medium, and a pair of transparent members are received in an integrally assembled state in the container. The solid laser medium and the pair of transparent members are each formed in a disc shape, and the solid laser medium is sandwiched between the pair of transparent members. The thermal conductivity of each of the pair of transparent members is higher than the thermal conductivity of the solid laser medium. The heat sink is shaped to simultaneously hold portions of the pair of transparent members that hold the solid laser medium in between. A heat insulation region having a lower thermal conductivity than the solid laser medium is provided between the heat sink and the solid laser medium.
    Type: Application
    Filed: November 24, 2005
    Publication date: April 17, 2008
    Applicants: OSAKA UNIVERSITY, HAMAMATSU PHOTONICS K.K.
    Inventors: Yasukazu Izawa, Masayuki Fujita, Shigeki Tokita, Tadashi Ikegawa, Toshiyuki Kawashima, Hirofumi Kan
  • Publication number: 20060133574
    Abstract: An object of the present invention is to provide an extreme ultraviolet light source target which can emits extreme ultraviolet light with high emission efficiency. A solid target made of heavy metal or heavy-metal compound and having a density 0.5 to 80% that of the crystal density is used. When the target is irradiated with a laser beam, plasma of the heavy metal contained in the target is generated, and extreme ultraviolet light having a predetermined wavelength which corresponds to the kind of the heavy metal is emitted from the plasma. When the density of the target is made to be smaller than the crystal density as described above, space distribution of the density of the generated plasma can be controlled, and the region in which plasma absorbs energy of the laser beam overlaps the region in which the plasma emits the extreme ultraviolet light. Thus, emission efficiency can be improved, preventing energy loss.
    Type: Application
    Filed: December 26, 2003
    Publication date: June 22, 2006
    Applicant: KANSAI TECHNOLOGY LICENSING ORGANIZATION CO., LTD.
    Inventors: Keiji Nagai, Hiroaki Nishimura, Takayoshi Norimatsu, Katsunobu Nishihara, Noriaki Miyanaga, Masahiro Nakatsuka, Yasukazu Izawa, Tatsuhiko Yamanaka, Mitsuo Nakai, Keisuke Shigemori, Masakatsu Murakami, Yoshinori Shimada, Shigeaki Uchida, Atsushi Sunahara, Vasilli Zhakhovski, Ryouji Matsui, Takahiro Hibino, Tomoharu Okuno
  • Publication number: 20050232318
    Abstract: A method and an apparatus capable of efficient laser amplification by cooling a semiconductor laser pumped, ytterbium doped YAG crystal to a temperature between 8 K and 230 K.
    Type: Application
    Filed: January 19, 2005
    Publication date: October 20, 2005
    Applicant: Japan Atomic Energy Research Institute
    Inventors: Junji Kawanaka, Masayuki Fujita, Yasukazu Izawa
  • Patent number: 5872804
    Abstract: A passive eight-pass solid-state laser amplifier is constructed using a quarter-wave plate (11), a total reflection mirror (12), a polarization beam splitter (5), and a total reflection mirror (6) while input/output faces of a hexagonal zigzag slab solid-state laser medium (15) optically pumped are kept nearly perpendicular to pulsed laser light. Thermal birefringence takes place in the laser medium (15) optically pumped with good symmetry by flash lamps or LDs (9) and is compensated for by a quartz 90.degree. rotator (10). Linearly s-polarized laser light reflected by a polarization beam splitter (3) is output as pulsed laser output light (13) to the outside. Owing to this, saturation laser amplification can be achieved using output laser light from a pulsed laser oscillator of relatively low output, as source light.
    Type: Grant
    Filed: July 17, 1997
    Date of Patent: February 16, 1999
    Assignees: Hamamatsu Photonics K.K., Institute for Laser Technology, Sadao Nakai, Yasukazu Izawa
    Inventors: Hirofumi Kan, Yasukazu Izawa, Masanobu Yamanaka, Hiromitsu Kiriyama, Takuji Yoshida, Sadao Nakai, Chiyoe Yamanaka
  • Patent number: 5587793
    Abstract: A sample is placed between a circular polarizer and an analyzer in an optical path between a monochromatic light source and a two-dimensional optical receiver. Parallel beams emitted from the monochromatic light source are converted into circularly polarized light by the circular polarizer. After transmitting the sample, the light is guided to the analyzer. While rotating the analyzer about the axis of the beams, image data are detected by optical receiver at a step of a regular rotation angle, and the detected image data are sampled to be sent to an image processing device in the next stage. On the basis of the image data, an operation is conducted on each pixel to obtain a relative phase difference due to birefringence of the sample, the two-dimensional birefringence distribution including the sign of the relative phase difference, and also the principal axis direction.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: December 24, 1996
    Assignees: Sadao Nakai, Institute for Laser Technology, Fuji Electric Co., Ltd.
    Inventors: Sadao Nakai, Yasukazu Izawa, Masanobu Yamanaka, Masato Ohmi, Masanori Akatsuka, Chiyoe Yamanaka, Yoshiyuki Yonezawa