Using a coherent-potential approximation, in conjunction with the on-shell method we developed for the study of photonic crystals, we study the effect of moderate disorder on light absorption by composite materials consisting of plasma spheres embedded in a host dielectric medium. We analyze our results by reference to the properties of a single sphere and to those of an infinite crystal. We find, in particular, that the absorption of light by a thin slab (a two-dimensional array of plasma spheres) is affected more strongly by disorder, in comparison to the absorbance of thick slabs consisting of many layers of spheres.

We developed a multiple scattering method for the calculation of the frequency band structure of a phononic crystal consisting of non-overlapping elastic spheres arranged periodically in a host medium of different elastic properties. Using a variation of the same method we can also calculate, with the same ease and accuracy, the coefficients of transmission, reflection and absorption of elastic waves incident on a slab of the material of finite thickness. The elastic coefficients of the spheres and/or the host medium can be complex and frequency dependent. We demonstrate the effectiveness of the method by applying it to specific examples.

We present a theory of electron, electromagnetic, and elastic wave propagation in systems consisting of non-overlapping scatterers in a host medium. The theory provides a framework for a unified description of wave propagation in three-dimensional periodic structures, finite slabs of layered structures, and systems with impurities: isolated impurities, impurity aggregates, or randomly distributed impurities. We point out the similarities and differences between the different cases considered, and discuss the numerical implementation of the formalism.

A brief introduction of the layer-Korringa-Kohn-Rostoker method for calculations of the frequency band structure of photonic crystals and of the transmission and reflection coefficients of light incident on slabs of such crystals is followed by two applications of the method. The first relates to the frequency band structure of metallodi-electric composites and demonstrates the essential difference between cermet and network topology of such composites at low frequencies. The second application is an analysis of recent measurements of the reflection of light from a slab of a colloidal system consisting of latex spheres in air.

We examine the optical properties of metals containing a periodic arrangement of nonoverlapping spherical mesopores, empty or filled with a dielectric material. We show that a slab of such a porous metal transmits light over regions of frequency determined by the dielectric constant of the cavities and the fractional volume occupied by them, with an efficiency, which is many orders of magnitude higher than predicted by standard aperture theory. Also, the system absorbs light efficiently over the said regions of frequency unlike the homogeneous metal.

Stacking faults appear to be the most common type of defect in inverted opals which are good candidates for photonic crystals with absolute gaps in the visible range of light. In this Letter we present for the first time a systematic study of the effect of stacking faults on the optical properties of self-assembled photonic crystals, by means of large-scale transmittance calculations for macroscopic slabs of inverted opals with randomly distributed stacking faults. We show that frequency gaps, as seen in optical transmission experiments, will in general appear wider in the presence of stacking faults. We attribute the above to Anderson localization of light due to disorder.