The stationary spectrum of individual dipole emitters in plasmonic nanocavities has been studied for a range of cavity geometries and dipole configurations. Less is known about the coherent dynamics of single photon creation in the nanocavity near field by an excited dipole. We address this gap by developing a Lorentzian kernel approximation that solves the time-dependent Schrödinger equation that describes the coupled dipole-photon dynamics in the single-excitation manifold. Our approach encodes the broadband nature of the nanocavity field through a non-Markovian memory kernel, derived from macroscopic QED theory. For a two-level dipole near a metallic nanosphere, we show that the single photon probability density in frequency space evolves in strong coupling from an initially localized source at the qubit frequency into a Rabi doublet over a timescale governed by the kernel spectrum. This dynamical crossover is accompanied by the formation of single-photon interference patterns in frequency and time, propagating coherently over a timescale limited by the shape of kernel spectrum to
∼100−150 fs, which is accessible to ultrafast spectroscopy. We also show that the stationary spectrum of the coupled system can be manipulated by driving the nanocavity field using coherent pulses with variable spectral bandwidth. Using single-photon pulses narrower than the kernel spectrum, the Rabi splitting in a system that supports strong coupling can be effectively removed. The applicability of our results to other dipole-nanocavity configurations is discussed and a general strong coupling criterion for nanocavities is formulated.
We present a general formalism and specific implementation of quantum gates based on interaction of single photons with open dissipative nanocavities containing ensembles of quantum emitters. Rich dynamics of entangled bright and dark states of quantum emitters coupled to a nanocavity field gives rise to efficient manipulation of the quantum state of an incident photon. In its simplest implementation, an initial preparation of the state of quantum emitters by a classical optical pulse controls the polarization state of the reflected photon.