Layered synthetic microstructures as Bragg diffractors for X rays and extreme ultraviolet: theory and predicted performance.

Recent developments in thin film technology have made possible the construction of multilayered thin film structures that act as efficient Bragg diffractors for x rays and extreme ultraviolet (EUV) radiation. These structures (which we term layered synthetic microstructures or LSMs) are analogous to multilayer interference filters for the visible spectral region and have important potential applications in many areas of x-ray/EUV instrumentation. In this paper the theory of x-ray diffraction by periodic structures is applied to LSMs, and approximate formulas for estimating their performance are presented. A more complete computation scheme based on optical multilayer theory is described, and it is shown that, by adjusting the refractive indices and thicknesses of the component layers, the diffracting properties may be tailored to specific applications. Finally, it is shown how the theory may be modified to take account of imperfections in the LSM structure and to compute the properties of nonperiodic structures.