Long-living collective optical excitations in a linear chain of microspheres

We consider propagation of optical modes in the chain of identical spheres. Optical coupling between whispering gallery modes of individual spheres result in formation of bands supporting propagation of optical excitations along the chain. Most of these bands, however, overlap resulting in strong inter-band mixing effects, which significantly influence both dispersions and radiative losses of the respective modes. We develop a general theory of these effects for the cases of weak inter-band mixing, and discuss its results in the context of recent experiments. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)