Potential of dry etching for the fabrication of fused silica micro-optical elements

We report on recent progress in the fabrication of fused silica micro-optical elements, such as blazed gratings, refractive microlenses and microprisms. The elements are first made in photoresist and then they are transferred into fused silica by reactive ion etching. High selectivity etching is needed to realize structures with a high aspect ratio. Results are shown using various metallic etch masks. The shaping of optimized profiles is also presented to generate microlenses which are aspheric, or which have a low numerical aperture.