MASKLESS WRITING OF SUBMICROMETER GRATINGS IN FUSED-SILICA BY FOCUSEDION-BEAM IMPLANTATION AND DIFFERENTIAL WET ETCHING

Surface relief gratings with submicrometer periods have been fabricate d in silica by ion implantation with a focused ion beam, followed by e tching in diluted hydrofluoric acid. Implanted silica etches three tim es faster than unimplanted silica and groove depths of the order of 30 0 nm have been achieved. The method does not require photolithography or masking layers, allows arbitrary patterns to be defined, and may be used to fabricate diffractive optical elements or grating filters in optical waveguides.