Quasinormal mode theory and applications of light-matter interactions in nanoplasmonics

We describe a quasi-normal mode (QNM) theory of light-matter interactions in nanoplasmonics. We first use a QNM expansion technique to obtain the photon Green function and compute the enhanced spontaneous emission rate from a quantum dot as a function of frequency; these QNM calculations show excellent agreement with full dipole finite-difference time-domain simulations and we also obtain a rigorous definition of the generalized effective mode volume for the localized surface plasmon mode. Using the examples of a single gold nanorod and a gold dimer of identical nanorods, we demonstrate why the Purcell factor is not the correct metric for describing enhancement spontaneous emission for dipole emitters away from the field antinode position, and we also show how the dimer structure can be used as an efficient single photon source. Exploiting a quantum master equation approach in combination with the QNM Green function theory, we shown examples of the Mollow triplet spectrum from a field-excited quantum dot in the vicinity of the gold nanorod and we discuss how to include Ohmic losses and quasistatic coupling in a fully analytic way. Finally, we show how to exploit the QNM theory to solve the local field problem for a finite-size photon emitter embedded inside a lossy metal nanorod.