Phase zone plates for hard X-ray microscopy

Phase zone plates are commonly used in X-ray microscopy techniques when high spatial resolution and high photon flux in the focal spot are desired. Extending the fabrication techniques of phase zone plates for use in the soft X-ray region to higher photon energies becomes difficult due to the high aspect ratios of the zone structures which have to be created. As an alternative, the sputtered sliced zone plate method has been applied. In this technology, a thin microwave is deposited alternately with two different materials. Zone plates are generated from the rod by slicing it perpendicular to its axis and thinning the slices down to the required zone plate thickness. Theoretical investigations on the demands on generating these zone plates as well as the generation process are discussed. Recent measurements will be presented.