Figuring sequences on a supersmooth sample using ion beam technique

An ion beam figuring facility is operational at the Centre Spatial de Liege since 1997. Its present capabilities are described. An extensive characterization program is running in order to determine the optimized parameters for various materials and operating conditions. In this frame, tests have been performed on a spherical gold-coated aluminum mirror plated in between the with nickel. The nickel plating was used to be super-polished to a BRDF of 1 10-4 at 1 deg at 10 micrometers wavelength. Micro-roughness and etching rate measurements were realized and influence of ion bombardment on the coating has been established after removal of the gold coating. The gold coating removal of the gold coating. The gold coating removing was performed by using the ion beam flux. Finally, the mirror has been figure from the original sphere to a parabola. Surface characteristics evolution is also described in terms of micro-roughness and surface error. An overview of the research and development programs related to this facility is given. Results of this technique and potential impact on optics fabrication are then briefly exposed.