Modal theory of modified spontaneous emission of a quantum emitter in a hybrid plasmonic photonic-crystal cavity system

We present an intuitive and accurate modal description of the rich optical physics involved for quantum dipole emitters coupled to hybrid plasmonic photonic-cavity structures. A significant frequency dependence for the spontaneous emission decay rate of a quantum dipole emitter coupled to these hybrid structures is found. In particular, it is shown that a Fano-type resonance reported experimentally in hybrid plasmonic systems arises from a large interference between two dominant quasinormal modes of the systems in the frequency range of interest. The presented modal theory forms an efficient basis for modeling quantum light-matter interactions in these complex hybrid systems and also enables the quantitative prediction and understanding of both radiative and nonradiative coupling for a wide range of dipole positions.