H
Hirokatsu Yumoto
Researcher at Osaka University
Publications - 121
Citations - 3555
Hirokatsu Yumoto is an academic researcher from Osaka University. The author has contributed to research in topics: Laser & Free-electron laser. The author has an hindex of 28, co-authored 112 publications receiving 3162 citations.
Papers
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Journal ArticleDOI
Breaking the 10 nm barrier in hard-X-ray focusing
Hidekazu Mimura,Soichiro Handa,Takashi Kimura,Hirokatsu Yumoto,Daisuke Yamakawa,Hikaru Yokoyama,Satoshi Matsuyama,Kouji Inagaki,Kazuya Yamamura,Yasuhisa Sano,Kenji Tamasaku,Yoshinori Nishino,Makina Yabashi,Tetsuya Ishikawa,Kazuto Yamauchi +14 more
TL;DR: In this paper, an in situ technique that corrects for wavefront aberrations and allows X-rays to be focused to a spot just 7 nm wide could provide a solution.
Journal ArticleDOI
Focusing of X-ray free-electron laser pulses with reflective optics
Hirokatsu Yumoto,Hidekazu Mimura,Takahisa Koyama,Satoshi Matsuyama,Kensuke Tono,Tadashi Togashi,Yuichi Inubushi,Takahiro Sato,Takashi Tanaka,Takashi Kimura,Hikaru Yokoyama,Jangwoo Kim,Yasuhisa Sano,Yousuke Hachisu,Makina Yabashi,Haruhiko Ohashi,Hitoshi Ohmori,Tetsuya Ishikawa,Kazuto Yamauchi +18 more
TL;DR: In this paper, the authors focus 10 keV X-ray free-electron laser radiation to an area of 0.95 µm × 1.20 µm with near-100%-efficiency using reflective optics.
Journal ArticleDOI
Efficient focusing of hard x rays to 25 nm by a total reflection mirror
Hidekazu Mimura,Hirokatsu Yumoto,Satoshi Matsuyama,Yasuhisa Sano,Kazuya Yamamura,Yuzo Mori,Makina Yabashi,Yoshinori Nishino,Kenji Tamasaku,Tetsuya Ishikawa,Kazuto Yamauchi +10 more
TL;DR: In this article, the authors developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interference.
Journal ArticleDOI
X-ray two-photon absorption competing against single and sequential multiphoton processes
Kenji Tamasaku,Eiji Shigemasa,Yuichi Inubushi,Tetsuo Katayama,Kei Sawada,Hirokatsu Yumoto,Haruhiko Ohashi,Hidekazu Mimura,Makina Yabashi,Kazuto Yamauchi,Tetsuya Ishikawa +10 more
TL;DR: In this article, the first observation of a third-order process induced by an X-ray beam from a free-electron laser is realized in germanium using a 5.6-keV X ray beam.
Journal ArticleDOI
Single-nanometer focusing of hard x-rays by Kirkpatrick–Baez mirrors
Kazuto Yamauchi,Hidekazu Mimura,Takashi Kimura,Hirokatsu Yumoto,Soichiro Handa,Satoshi Matsuyama,Kenta Arima,Yasuhisa Sano,Kazuya Yamamura,Koji Inagaki,Hiroki Nakamori,Jangwoo Kim,Kenji Tamasaku,Yoshinori Nishino,Makina Yabashi,Tetsuya Ishikawa +15 more
TL;DR: An at-wavelength wavefront error sensing method based on x-ray interferometry and an in situ phase compensator mirror, which adaptively deforms with nanometer precision, were developed to satisfy the Rayleigh criterion to achieve diffraction-limited focusing in a single-nanometer range.