We introduce a second quantization scheme based on quasinormal modes, which
are the dissipative modes of leaky optical cavities and plasmonic resonators
with complex eigenfrequencies. The theory enables the construction of
multi-plasmon/photon Fock states for arbitrary three-dimensional dissipative
resonators and gives a solid understanding to the limits of phenomenological
dissipative Jaynes-Cummings models. In the general case, we show how different
quasinormal modes interfere through an off-diagonal mode coupling and
demonstrate how these results affect cavity-modified spontaneous emission. To
illustrate the practical application of the theory, we show examples using a
gold nanorod dimer and a hybrid dielectric-metal cavity structure.Comment: 6 pages, 3 figure
