What will happen if two identical microspheres, with fundamental whispering-gallery modes excited in each of them, become optically coupled? Conventional wisdom based on coupled-mode arguments says that two new modes, bonding and antibonding, with two split frequencies would be formed. In this Rapid Communication, we demonstrate, using exact multisphere Mie theory, that in reality an attempt to couple two fundamental modes of microspheres would result in a complex multiresonance optical response with the field distribution significantly deviating from predictions of coupled-mode-type theories.

• Received 12 October 2007

DOI:https://doi.org/10.1103/PhysRevA.77.051801