Generation of 10(20) W cm(-2) hard X-ray laser pulses with two-stage reflective focusing system.

Mimura, Hidekazu; Yumoto, Hirokatsu; Matsuyama, Satoshi; Koyama, Takahisa; Tono, Kensuke; Inubushi, Yuichi; Togashi, Tadashi; Sato, Takahiro et al. · Nat Commun · 2014

basic_science · Level V

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Abstract

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.