The localization of electromagnetic waves in lossless inhomogeneous dielectric media is studied. We consider a three-dimensional lossless periodic medium (photonic crystal) having a gap in the frequency spectrum (photonic bandgap). If such a medium is perturbed by either a single defect or a random array of defects, exponentially localized electromagnetic waves arise with frequencies in the gap. For a single defect, we derive equations for these midgap frequencies and estimate their number. For a random medium, we show the occurrence of Anderson localization for electromagnetic waves.
© 1998 Optical Society of America
Alexander Figotin and Abel Klein, "Localization of light in lossless inhomogeneous dielectrics," J. Opt. Soc. Am. A 15, 1423-1435 (1998)