LAUSR

Abstract Nanocavity mediated directional coupler in plasmonics waveguides is proposed and numerically investigated. Perfect directionality with enhanced light intensity coupled to the desired direction is obtained through the chiral eigenmode of the nanocavity excited by an elliptically polarized dipole. The directionality is robust to the position and polarization of the dipole. Furthermore, both circular and Huygens types of sources have been demonstrated through the tunable coupling length between the nanocavity and the straight waveguide. This proposal provides a versatile method to unidirectionally control the light flow through the near-field coupling, which might provide opportunities for on-chip optical circuits, either quantum or classical.