A highly efficient nanofocusing system for soft x rays

Yoko Takeo, Hiroto Motoyama, Takenori Shimamura, Takashi Kimura, Takehiro Kume, Yusuke Matsuzawa, Takahiro Saito, Yoichi Imamura, Hiroaki Miyashita, Kentaro Hiraguri, Hirokazu Hashizume, Yasunori Senba, Hikaru Kishimoto, Haruhiko Ohashi, Hidekazu Mimura

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The focusing of x rays is essential in various types of x-ray microscopy because the size and flux of the illuminating beam determine the spatial resolution and signal intensity, respectively. A system with grazing incidence mirrors allows highly efficient x ray focusing with beam dimensions on the nanometer scale. Tube-shaped mirrors with a large numerical aperture and high demagnification, including ellipsoidal mirrors and Wolter mirrors, have recently been developed for soft x-ray nanofocusing. However, these mirrors have low efficiency because they cannot focus the central part of the illumination beam. Here, we propose a two-stage focusing system, in which a ring-shaped beam formed by a ring-focusing mirror illuminates a quasi-Wolter mirror. A prototype of the system is experimentally constructed at beamline BL25SU-A of SPring-8. Observation of the wavefront error based on ptychography enables efficient alignment of the two mirrors. Using this alignment procedure, we achieve a spot size of less than 200 nm at 300 eV.

Original languageEnglish
Article number0027118
JournalApplied Physics Letters
Issue number15
Publication statusPublished - Oct 12 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)


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