Propagation of light through localized coupled-cavity modes in one-dimensional photonic band-gap structures

We report on the observation of a new type of propagation mechanism through evanescent coupled optical cavity modes in one-dimensional photonic crysta ls. The crystal is fabricated from alternating silicon-oxide/silicon-nitrid e pairs with silicon-oxide cavity layers. We achieved nearly full transmiss ion throughout the guiding band of the periodic coupled cavities within the photonic band gap. The tight-binding (TB) parameter kappa is determined fr om experimental results, and the dispersion relation, group velocity and ph oton lifetime corresponding to the coupled-cavity structures are analyzed w ithin the TB approximation. The measurements are in good agreement with tra nsfer-matrix-method simulations and predictions of the TB photon picture.