PHOTON FOCUSING, INTERNAL DIFFRACTION, AND SURFACE-STATES IN PERIODICDIELECTRIC STRUCTURES

Several analogies between electrons and phonons in semiconductors and electromagnetic waves in periodic dielectric structures are used to de monstrate the existence of (i) surface or edge states at the boundarie s between the periodic structure and air, (ii) focusing of the electro magnetic energy emitted by a point source, and (iii) the existence of internal diffraction as known for coherent acoustic waves. In addition , the inclusion in phonon or electron band structures, is briefly disc ussed.