PHOTONIC BANDTAIL IN 1D RANDOMLY-PERTURBED PERIODIC-SYSTEMS

The results of a detailed numerical study of the optical bandtail in a 1D randomly-perturbed periodic system are reported. It is found that the width of the optical bandtail grows proportionally to the magnitud e of the random perturbations. and the states in the bandtail regime, which are tightly localized, are separated from the more extended stat es in the pass band by a quasi mobility edge. Frequency dependence of the localization length and its relation to the distribution of the ra ndom perturbations are also examined.