Bragg-Fresnel Multilayer Optics for X-ray Microscopy and Spectroscopy

Abstract

Application of metallic multilayer mirrors for construction of different components of x-ray optical schemes became more and more frequent. Number of publications gives an examples of objective lenses, monochromators, focusing and imaging devices, based on figured multilayer mirrors. One of the most exited application of such optics in future can be projection X-ray lithography and local analyses of microstructures with submicron resolution for microelectronics technology. Recently, focusing and imaging by the use of some kinds of "grooved" diffraction optics on flat surfaces instead of the curved substrate had been reported in several papers. This optics is now known as Bragg-Fresnel Multilayer Optics (BFMO) [1,2]. Compared to grazing incidence optics and figured multi-layers optics, BFMO can provide higher spatial and spectral resolutions. That is say, till to spot value up to 0.1μ spatial resolution of BFMO is limited only by the flatness of the plane substrate and accuracy of the lithographic process [3]. In principle BFMO combines the high spatial resolution of Fresnel zone plates and the high radiation stability of multi-layer X-ray mirrors. This report gives an examples of fabrication, computer simulation and tests for two kind of BFMO: Lamellar Multilayer Gratings (LMG) and Linear Bragg-Fresnel Multilayer Lenses (LBFML). LMG, used here as the first step for the understanding of diffraction property of LBFML, can be very interesting themselves as by spectroscopic instruments with relatively high dispersion and efficiency.