Propagation of electromagnetic waves in 1D finite photonic crystals for the investigation of linear properties

Abstract

In present work, the transmittance, Bloch wavevector, group velocity, group index, photon delay and effective gain has been analyzed by computer simulation. The group velocity vanishes at the edges of forbidden band gaps at normalized frequencies 0.2922, 0.4199, 0.6608 and 0.7822, where photons are localized. This results in the superluminal group velocity being increased and causes a large decrement in group index. We have obtained a small value of group velocity at the photonic band edges which represents the available density of states of photon localization. Photons percolating through the layers make many passes (being reflected between the layers) and slow down as they pass through the active layers, which increase the optical path length and optical gain. The photon delay factor has been observed to be dominant as the group velocity approaches zero. Our analysis explores the applicability of 1D photonic crystal for threshold-less lasing.