Designing Fano-Like Quantum Routing via Atomic Dipole-Dipole Interactions**Supported by the National Natural Science Foundation of China under Grant No 11247032, the Natural Science Foundation of Jiangxi Province under Grant Nos 20151BAB202012 and 20151BAB212004, and the Scientific Research Foundation of the Jiangxi Provincial Education Department under Grant No GJJ160633.

Abstract

Fano-like quantum routing of single photons in a system with two waveguides coupled to two collocated atoms is investigated theoretically. Using a full quantum theory in real space, photonic scattering amplitudes along four ports of the waveguide network are analytically obtained. It is shown that, by adjusting the atomic dipole-dipole interaction, an evident Fano-line shape emerges in the scattering spectra of the single-dot configuration system. Moreover, Fano resonance can also be achieved by varying the atom-waveguide coupling strength and atomic detuning, in the presence of the atomic dipole-dipole interaction. Therefore, the atomic dipole-dipole interaction may be utilized as a possible way to control spectral Fano-like resonance. The feasibility with the experimental waveguide channels is also discussed.