Nanomachining of hard X-ray crystal optics

Recent technological developments in visible, IR and UV optics are step by step being implemented also in XUV, soft X-ray and even in hard X-ray optics for > 5 keV photon energies. The older stochastic technologies are still valuable for open planar and simple (spherical, cylindrical) curved surfaces, but modern deterministic technologies based on ultraprecise axes and single point diamond tools mean important technological progress in ultraprecise surface shaping also for more complex surfaces. When decreasing depth of cut below critical depth of cut, material removal mechanism changes from brittle through brittle-ductile to ductile regime even for brittle materials such as single crystal silicon and germanium. Several types of technologies (single point diamond turning, flycutting, slow slide servo, micromilling) were used to prepare simple and special surfaces on Si, Ge, and Cu single crystals for X-ray beam conditioning and shaping optical elements (compressors and expanders). Their surface roughness, subsurface damage and shape precision, measured by means of AFM, micro Raman spectroscopy, reciprocal space mapping, and Dektak profilometry, are presented and discussed.