Normal mode splitting induced by a local Rayleigh scatterer in a microsphere resonator: transition from weak to strong coupling

This study investigates a system which provides an analogy between cavity quantum electrodynamic (CQED) effects (dipole and cavity) and the modal coupling of high-Q modes in an optical microresonator induced by a Rayleigh scatterer. This is accomplished by utilizing a scanning near field optical microscope tip as a controllable Rayleigh scatterer. Analysis in terms of CQED provides a better understanding of the large mode splitting previously observed in microresonators.