Hard X-ray diffraction-limited nanofocusing with Kirkpatrick-Baez mirrors

Nanofocused X-ray beams are necessary for nanometer-scale spatial microscopy analysis. X-ray focusing using a Kirkpatrick-Baez setup with two total reflection mirrors is a promising method, allowing highly efficient and energy-tuneable focusing. In this paper, we report the development of ultraprecise mirror optics and the realization of a nanofocused hard-X-ray beam. Fabricated mirrors having a figure accuracy of 2 nm peak to valley height give ideal diffraction-limited focusing at the hard X-ray region. The focal size, defined as the full width at half maximum in the intensity profile, was 36 nm x 48 nm at an X-ray energy of 15 keV.