X-ray focusing with efficient high-NA multilayer Laue lenses

High-quality, multilayer Laue lenses that can focus hard X-rays to a spot smaller than 10 nanometers have been fabricated. Multilayer Laue lenses—oriented artificial crystals that focus X-rays by Bragg diffraction—can be used to focus and image with hard X-rays. Now, Sasa Bajt of DESY in Hamburg, Germany, and co-workers have fabricated a pair of high-numerical-aperture Laue lenses for performing focusing in two directions. Each lens is a volume zone plate that acts as a diffractive optical element and is composed of several thousand alternating layers of silicon carbide and tungsten carbide. When separated by 0.6 millimeters, the two lenses were able to focus hard X-rays to a 8.4 nanometers by 6.8 nanometers spot. An error analysis indicates that it may be possible to achieve X-ray focusing of about 1 nanometer.