Lord Kelvin defines a peculiar geometrical symmetry breaking which was later shown by Luis Pasteur to affect important chemical properties of molecules. In addition, chiral structures have shown to induce symmetry breaking optical phenomena with respect to the circularly polarized light – optical activity. General natural materials produce very weak optical activity, requiring large amounts of bulk chiral medium to be incorporated. Recently, much more significant optical activity was demonstrated in nanophotonic devices based on surface plasmon polaritons (SPP).
These surface confined electromagnetic waves propagating in conducting surfaces were shown to play an important role in optical spin-orbit interaction. Specifically, it was demonstrated that the propagation of the surface plasmon polaritons can be severely affected by the exciting light's polarization handedness. Depending on the system geometry, a weakor a strong spin-orbit coupling was demonstrated.
In the common basis of those phenomena lies the principle of optical angular momentum conservation due to rotational symmetry.
In the present work we propose a surface plasmon polaritons based optical device, which efficiently routes the propagating light based on the incident polarization handedness to either left or right arm of the structure.