Design of Hard X-Ray Fresnel Zone Plates Based on Rigorous Coupled Wave Theory

The Fresnel zone plate (FZP) enabling the focusing of light sources is one of the main components in hard X-ray microscopy. Resolution and diffraction efficiency are the two most important parameters of FZP, which, however, are often difficult to be considered at the same time in actual design and preparation. Therefore, a design method for hard X-ray FZP based on rigorous coupled wave theory is proposed in this paper. The method optimizes the diffraction efficiency based on the specified resolution and gives the optimized values of the composition materials, the width of the ring zone, the outer diameter, the thickness, and the thickness control accuracy associated with the hard X-ray FZP. Furthermore, considering the influence of material dispersion, the distribution of the optimal diffraction efficiency with the change in the light source energy is given, which provides a reference for the light source selection in microscopic imaging.