Dye-containing polymer beads as photonic crystals

Monodisperse PMMA beads of a size varying between 200 and 400 nm have been prepared by a modified emulsion polymerization technique. These beads sediment well on substrates to form 3-dimensional face-centered cubic packages. This method allows it to cover large glass substrates (area up to 10 x 10 cm) with an opalescent layer of the beads thus creating films with opaline structure, which can be used as photonic crystals. Choosing PMMA as the material of the beads brings several advantages, e.g., the PMMA photonic films can be precisely patterned by e-beam lithography with the feature resolution down to one bead in width and various fluorescent dyes can be incorporated in PMMA balls. Dye-impregnated PMMA opaline photonic films demonstrate the incomplete photonic band gap structure and related modification of dye photoluminescence spectrum.