Generation of 1020 W cm−2 hard X-ray laser pulses with two-stage reflective focusing system

• DOI: 10.1038/ncomms4539
• Publication Date: 2014-04-30T10:41:13Z
• Authors: Hidekazu Mimura; Hirokatsu Yumoto; Satoshi Matsuyama; Takahisa Koyama; Kensuke Tono; Yuichi Inubushi; Tadashi Togashi; Takahiro Sato; Jangwoo Kim; Ryosuke Fukui; Yasuhisa Sano; Makina Yabashi; Haruhiko Ohashi; Tetsuya Ishikawa; Kazuto Yamauchi
• Keywords: Aperture (computer memory); X-ray optics; Power density

Intense X-ray fields produced with hard X-ray free-electron laser (XFEL) have made possible the study of nonlinear X-ray phenomena. However, the observable phenomena are still limited by the power density. Here, we present a two-stage focusing system consisting of ultra-precise mirrors, which can generate an extremely intense X-ray field. The XFEL beam, enlarged with upstream optics, is focused with downstream optics that have high numerical aperture. A grating interferometer is used to monitor the wavefront to achieve optimum focusing. Finally, we generate an extremely small spot of 30 × 55 nm with an extraordinary power density of over 1 × 10(20) W cm(-2) using 9.9 keV XFEL light. The achieved power density provides novel opportunities to elucidate unexplored nonlinear phenomena in the X-ray region, which will advance development on quantum X-ray optics, astronomical physics and high-energy density science.