H
Hikaru Yokoyama
Researcher at Osaka University
Publications - 12
Citations - 843
Hikaru Yokoyama is an academic researcher from Osaka University. The author has contributed to research in topics: Wavefront & Adaptive optics. The author has an hindex of 7, co-authored 12 publications receiving 768 citations.
Papers
More filters
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
Wavefront measurement for a hard-X-ray nanobeam using single-grating interferometry.
Satoshi Matsuyama,Hikaru Yokoyama,Ryosuke Fukui,Yoshiki Kohmura,Kenji Tamasaku,Makina Yabashi,Wataru Yashiro,Atsushi Momose,Tetsuya Ishikawa,Kazuto Yamauchi +9 more
TL;DR: Wavefront measurement for a hard-X-ray nanobeam using single-grating interferometry based on the Talbot effect and the Fourier transform method was demonstrated in the 1-km-long beamline of SPring-8, demonstrating good agreement with each other and with the wavefront error estimated from the shape of the deformable mirror.
Journal ArticleDOI
Wavefield characterization of nearly diffraction-limited focused hard x-ray beam with size less than 10 nm.
Takashi Kimura,Hidekazu Mimura,Soichiro Handa,Hirokatsu Yumoto,Hikaru Yokoyama,Shota Imai,Satoshi Matsuyama,Yasuhisa Sano,Kenji Tamasaku,Yoshiki Komura,Yoshinori Nishino,Makina Yabashi,Tetsuya Ishikawa,Kazuto Yamauchi +13 more
TL;DR: A one-dimensionally focused beam with a width of 7 nm at 20 keV using a multilayer mirror is characterized and it is demonstrated that the wavefront can be determined precisely from multiple intensity profiles measured around the beamwaist.
Proceedings ArticleDOI
An adaptive optical system for sub-10nm hard x-ray focusing
Hidekazu Mimura,Takashi Kimura,Hikaru Yokoyama,Hirokatsu Yumoto,Satoshi Matsuyama,Kenji Tamasaku,Y. Koumura,Makina Yabashi,Tetsuya Ishikawa,Kazuto Yamauchi +9 more
TL;DR: In this article, an adaptive optical system for sub-10nm hard X-ray focusing was developed, which performs the wavefront measurement using a phase retrieval algorithm and wavefront control using grazing incidence deformable mirrors.