Leak-free bound modes in photonic crystal films

Summary form only given. Two-dimensional photonic crystal films typically consist of an array of holes etched into a planar substrate, usually itself incorporating a planar dielectric waveguide. Many applications are suggested for such structures, key among them being integration, at high packing densities, of highly miniaturised photonic components. This will, however, not work unless the light is properly within the 2-D plane of the photonic crystal. Although a degree of leakage may be acceptable in a photonic crystal mirror, where the light penetrates only a few periods, this is no longer true if several devices are concatenated. We outline the key steps in designing photonic crystal films that support bound modes, building on previously published work. The generic structure consists of a high index film with an array of holes drilled into it, a substrate of lower index n/sub SS/ and a cover of even lower index. Variations on this structure might have holes which penetrate deep into the substrate and cover.