Design and fabrication of new optics for X-ray microscopy and material science

The current intense interest in extreme ultraviolet and X-ray microscopy is mainly due to the availability of a nearly ideal optical source for diffractive optics (i.e. a source with low divergence whose wavelength can be tuned over a range of several keV and whose spectrum has a band pass Δλ/λ of less than 10^-4). The aim of this paper is to introduce novel X-ray diffractive optics that, beside simple focusing, perform new optical functions. In particular, the intensity of the beam in the space after the optical elements can be redistributed with almost complete freedom. Using our own code we have designed high resolution diffractive elements which focus the monochromatic X-ray beam into multiple spots displaced in a single or more planes along the optical axis. These optical elements have been fabricated by means of e-beam lithography. Their functionality has been tested in two different X-ray microscopes: the scanning and the full-field imaging microscopes using the differential interference contrast method. We report experimental imaging results obtained with phase objects (PMMA and biological samples) and fluorescence measurements with important impact in the material science applications.