Mode coupling and enhanced Kerr nonlinearity with multiple Rayleigh scatterers containing a single dipole quantum emitter surrounding a whispering-gallery microcavity

We theoretically investigate a cavity quantum electrodynamics system in which a high-Q whispering-gallery-mode microcavity interacts simultaneously with a dipole quantum emitter and multiple Rayleigh scatterers. The scatterers are used to induce and to control mode coupling between counterclockwise and clockwise propagating light fields, which interact with the dipole quantum emitter. We study the effect of mode coupling on the linear and nonlinear output characteristics of coherent photon transport in a tapered fiber waveguide coupling the microcavity. It is found that enhanced optical Kerr nonlinearity with high linear transmission rate can be achieved efficiently when the system parameters are tuned properly. The present results illustrate the potential to utilize mode coupling for enhancing optical Kerr nonlinearities and controlling the transmission of light.