Ultra-precision surface finishing by ion beam and plasma jet techniques—status and outlook

Aspheric reflective optics are becoming more and more important for synchrotron radiation source and X-ray applications. The manufacture of such highly precise optical surfaces requires deterministic ultra-precision machining technologies.The article focuses on the present status of development of ion beam finishing technology and of atmospheric plasma jet technology in Leibniz Institute of Surface Modification (IOM). The basics of the ion beam and the plasma jet processing technologies and the respective equipment and components developed or being under development for production purposes will be presented together with results on the ion beam figuring (IBF), ion beam smoothing (IBS), and the deep figuring and figure correction using atmospheric plasma jet machining (PJM) technique, respectively. Using IBF and IBS, we achieve nanometer and sub-nanometer accuracies over nearly the entire spectrum of spatial surface wavelength on a variety of materials. PJM technique has been developed to obtain high removal rates especially on silicon-based materials. Removal depths of some 10 μm can easily be achieved.The article gives an outlook to future activities on developments of the techniques with respect to advanced X-ray optics.