Design and fabrication of broadband holographic ion beam etching gratings

A broadband holographic ion beam etching grating with three different blazed angles was designed and fabricated on the same substrate.A new divisional design method for the broadband holographic ion beam etching grating was proposed and the design parameters for the grating were optimized.A reactive ion beam etching equipment was used in the pattern transfer of photosensitive resist and the divided and stepped ion beam etching technology was used in the experiment.Finally,a broadband holographic ion beam etching grating with a diameter of 60mm×60mm worked at 200-900 nm was fabricated on a K9 substrate,which has the same phase but three different blazed angles of 9°,18°and 29°on different areas.The experimental results show that the lowest and the highest diffraction efficiencies of holographic ion beam etching grating are higher than 30% and 50%,respectively in the broadband of 200-900 nm,which is well in agreements with that of the theoretical calculation and meets thedesign requirements.As compared with other fabricating methods for grating,the proposed method is characterized by controllable groove shapes,larger sizes and to be easy for bulk fabrication.