Femto-second laser processing of polycrystalline CVD diamond was applied to manufacturing of X-ray planar refractive
lenses. Surface morphology and material quality were analyzed with optical and scanning electron microscopy and X-ray
radiography. Lenses were tested in a focusing mode at the IIIrd generation synchrotron radiation source (ESRF).
Refractive optics is proposed as a Fourier transformer for high resolution X-ray crystal diffraction. Employing refractive lenses the wave transmitted through the object transforms into spatial intensity distribution at its back focal plane according to the Fourier 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 SiO2 film on Si substrate and a grating made by profiling a Si crystal. Rocking curves of Si(111) Bragg reflection and corresponding Fourier patterns were analyzed.