Defect structures in a layer-by-layer photonic band-gap crystal

We have experimentally and theoretically investigated defect structures that are incorporated into a three-dimensional layer-by-layer photonic band-gap crystal. The defects are formed by either adding or removing dielectric material to or from the crystal. For both cases, we observed localized modes with frequencies that lie within the forbidden band gap of the pure crystal. Relatively high peak transmission (10 dB below the incident signal), and high quality factors (2000) have been measured. These measurements were in good agreement with theoretical simulations. Theoretical calculations also predict very high (Q>106) quality factors for certain cavity structures. © 1995 The American Physical Society.