X-ray refractive lenses are proposed as a Fourier transformer for high-resolution X-ray crystal diffraction. By employing refractive lenses the wave transmitted through the object converts into a spatial intensity distribution at its back focal plane according to the Fourier-transform relations. A theoretical consideration of the Fourier-transform technique is presented. Two types of samples were studied in Bragg reflection geometry: a grating made of strips of a thin SiO2film on an Si substrate and a grating made by profiling an Si crystal. Fourier patterns recorded at different angles along the rocking curves of the Si 111 Bragg reflection were analysed.
Design and performance of a soft-x-ray interferometer for ultra-high-resolution fourier transform spectroscopy