High-resolution lenses for sub-100 nm x-ray fluorescence microscopy

We report on the design, fabrication, and testing of Fresnel zone plates fo r high-resolution x-ray fluorescence microscopy using the scanning x-ray mi croscope at the European Synchrotron Radiation Source. The germanium lenses were optimized for operation near the sulphur absorption edge at 2472 eV p hoton energy. The high measured diffraction efficiencies of up to 9.6% and the good match to the spatial coherence of the undulator beam resulted in a photon flux of about 4x10(8) photons per second within the bandwidth of a silicon < 111 > monochromator. Using a test object consisting of zinc sulph ide nanostructures, we were able to image features in sulphur x-ray fluores cence mode with lateral dimensions down to below 100 nm. (C) 2000 American Institute of Physics. [S0003-6951(00)01149-9].