Quantum Electrodynamics of Quantum Dot-Metal Nanoparticles Molecules

We study theoretically the quantum optical properties of hybrid molecules composed of an individual quantum dot and a metallic nanoparticle. We calculate the resonance fluorescence of this hybrid system. Its incoherent part, the one arising from nonlinear quantum processes, results to be enhanced by more than two orders of magnitude as compared to that in the absence of the metallic nanoparticle. Scattering spectra at different excitation powers and nonperturbative calculations of intensity-field correlation functions show that this system can act as a nonlinear ultra-compact two-photon switch for incident photons, where the presence (or absence) of a single incident photon field is sufficient to allow (or prevent) the scattering of subsequent photons. We also find that a small frequency shift of the incident light field may cause changes in the intensity field correlation function of orders of magnitude.