Fano interference and transparency in a waveguide-nanocavity hybrid system with an auxiliary cavity* *Project supported by the National Natural Science Foundation of China (Grant Nos. 11774262 and 11975023).

Abstract

We investigate theoretically single photon transport in one-dimensional waveguide coupled to a pair of cavities, which are denoted by the first cavity and the auxiliary cavity. Two cases with no atom and one atom embedded in the first cavity are discussed. The Fano dips in the transmission spectrum and locations of transparency window are calculated. When no atom is embedded in the first cavity, there exists a transparency window under the condition that the first cavity and the auxiliary cavity are not resonant. The locations of the transparency window and Fano line type depend strongly on the eigen frequency of the auxiliary cavity and the coupling strength between the auxiliary cavity and the waveguide. When one atom is embedded in the first cavity, we show that the transparency window exists even though the first cavity, the atom and the auxiliary cavity are resonant. The Fano line type is strongly dependent on the eigen frequency of the auxiliary cavity and the coupling strength. Our results have potential applications in design of quantum devices at the level of single photon, such as single photon switch and single photon routers.