Usually, the liner waveguides with single quantum emitters are utilized as routers to construct the quantum network in quantum information processings. Here, we investigate the influence of the nonlinear dispersion on quantum routing of single surfac
e plasmons, between two metal nanowires with a pair of quantum dots. By using a full quantum theory in real space, we obtain the routing probabilities of a single surface plasmon into the four outports of two plasmonic waveguides scattered by a pair of quantum dots. It is shown that, by properly designing the inter-dot distance and the dot-plasmon couplings, the routing capability of the surface plasmons between the plasmonic waveguide channels can be significantly higher than the relevant network formed by the single-emitter waveguides with the linear dispersions. Interestingly, the present quadratic dispersions in the waveguides deliver the manifest Fano-like resonances of the surface-plasmon transport. Therefore, the proposed double-dot configuration could be utilized as a robust quantum router for controlling the surface-plasmon routing in the plasmonic waveguides and a plasmonic Fano-like resonance controller.
Quantum routing of single photons in a system with two waveguides coupled to two whispering-gallery resonators (WGRs) are investigated theoretically. With a real-space full quantum theory, photonic scattering amplitudes along four ports of the wavegu
ide network are analytically obtained. It is shown that, by adjusting the geometric and physical parameters of the two-WGR configuration, the quantum routing properties of single photons along the present waveguide network can be controlled effectively. For example, the routing capability from input waveguide to another one can significantly exceed 0.5 near the resonance point of scattering spectra, which can be achieved with only one resonator. By properly designing the distance between two WGRs and the waveguide-WGR coupling strengths, the transfer rate between the waveguides can also reach certain sufficiently high values even in the non-resonance regime. Moreover, Fano-like resonances in the scattering spectra are designable. The proposed system may provide a potential application in controlling single-photon quantum routing as a novel router.
