Optimisation of the prism coupling of optical whispering-gallery-mode microcavities

The methods for increasing the coupling efficiency of a prism with spheroidal microcavities, aimed at exciting whisperinggallery modes, have been analytically investigated. Optimal angles of incidence and incident beam parameters are obtained for a spheroidal cavity. The cavity eigenfrequency shift caused by the presence of a prism and the introduced loss by it is calculated.