A Three-Dimensional Photonic Crystal Operating in the Visible Region

Photonic bandgap materials have received considerable attention due to their ability to confine and control electromagnetic waves in all three spatial directions. The material reported here (see Fig.) is a cubic-close-packed (ccp) lattice assembled from 215 nm polystyrene beads whose surfaces have been doped with the organic dye Oil Blue N. The method gives large-area crystals and allows the tuning of the photonic bandgap through variation of dopant and bead size (see Cover).