Directional Coupling of Emitters into Waveguides: A Symmetry Perspective

Abstract Recent experiments demonstrate strongly directional coupling of light into waveguide modes. Here, the symmetry mechanisms behind this effect are studied, and it is shown that analysis symmetries symmetry‐breakings emitter‐waveguide system allows to qualitatively understand in several situations. The authors consider emitters either centered a median plane waveguide, or displaced from it, whose emissions have well‐defined angular momentum one two different axis typically chosen experimentally, which called transverse vertical. These insights matched by simulations, previous experimental measurements. It handedness plays secondary role coupling. spin‐momentum locking concept generalized an exponentially strong between preferential direction. A new selection rule obtained controls electric(magnetic) multipolar An experiment proposed featuring magnetic bias aggregates many quantum dots on top waveguides, contrast used vertical bias, effectively restricts using single dot. Finally, Huygens' dipole analyzed enable its behavior revealed.