Current Status and Future Challenges in Focusing Technology of X-Ray Free Electron Laser

Abstract

  Recent achievements and future challenges in mirror-based focusing devices for X-ray free electron laser are reviewed including a brief introduction of fabrication methods of highly accurate X-ray mirrors. KB (Kirkpatric-Baez) mirrors to focus the Japanese XFEL (X-ray free electron laser) down to 1 μm and sub-50 nm spot sizes, which have already been developed and installed into the XFEL facility, are discussed to reach the diffraction-limited focusing performances. Ultimately small spot size of sub-10 nm is now studied to be realized.