Focusing of electromagnetic fields in high-Q hybrid wedge plasmon polariton microresonator

We theoretically propose a hybrid microresonator consisting of a metallic wedge ring and a silica ring and investigate the existing whispering-gallery-like hybrid wedge plasmon polariton modes. These tightly confined hybrid plasmon modes are found to possess ultrasmall mode volumes while maintaining relatively high quality factors simultaneously at room temperature; that is, high values of Q/V are obtained. For example, a Purcell factor of 70 is achieved at the telecommunication wavelength of 1550 nm. This plasmon microresonator shows great potential in low-threshold plasmonic microlasers and cavity quantum electrodynamics.