Gratings and zone plates based on sliced multilayer structures

Abstract

A slice of ordinary multilayer structure represents a miniature sample cut out of layered media which can be used as a reflection or a transmission grating. The analysis shows very high flexibility of these gratings. Various properties can be achieved by proper design and choice of layer materials: (a) high angular dispersion due to submicron grating period, (b) high throughput in XUV range due to resonance Bragg effect, (c) high spectral resolution defined by the number of layer pairs in a sample (up to 1000), (d) focusing properties achieved by grading of multilayer period which is introduced in the process of deposition. The present status of research on reflection sliced multilayer grating is presented. If the multilayer coating is deposited onto a wire of submillimeter diameter then the slice of it represents a zone plate if the Fresnel law of layer thickness variation is provided. This sputter slice method is known to be a prospective technology for production of zone plates with increased diffraction efficiency, spectral selectivity and spatial resolution. The physical reason for it is the strong interaction of incident radiation with layered media which takes place in optically thick zone plates. The wave theory of high aspect ratio zone plates is given with the emphasis on practical design. The software capable to simulate diffraction characteristics of realistic zone plates, to calculate and visualize the global field distribution, optimize materials and geometry of zone plate is being developed.