Frequency-dependent cavity lifetime and apparent superluminality in Fabry-P´erot-like interferometers

摘要

Extraordinary group delays shorter than the transit time of light propagating at c through an equal distancenhave been experimentally demonstrated in single-Fabry-P´erot (FP)waveguide systems and cascaded-FP structuresnunder off-resonant conditions. These “superluminal” phenomena are well explained by the multiple-reflectionndestructive interference that reduces the intracavity stored energy when operating off resonances. Excellentnagreement between theory and experiment is obtained when the dispersive effects of reflective boundaries arenconsidered. These results provide further insight into the nature of apparent superluminality in regions of allowednpropagation.