Quantum hybrid plasmonic nanocircuits for versatile polarized photon generation

Hybrid plasmonic nanocircuits developed insofar enable efficient coupling and routing of single photons generated by embedded quantum emitters (QEs), providing at the same time little or no control over the polarization of out-coupled single photons. Here, with numerical simulations a QE-driven hybrid plasmonic nanocircuit for versatile polarized photon generation by using ultracompact polarization out-couplers in multi-branched dielectric-loaded plasmonic waveguides is proposed and demonstrated. Upon excitation of a QE, which is embedded at the center of a star-shaped six-branched hybrid plasmonic waveguide and characterized with a normal to the surface radiative transition dipole, plasmonic waveguide modes are efficiently (≈85%) excited and routed by the six-branched waveguide toward propitiously designed out-couplers. By exploiting two types of subwavelength polarization out-couplers producing linearly and circularly polarized free-space radiation, spatially separated single-photon generation channels characterized by four different linear and two circular polarizations are created. The demonstrated hybrid plasmonic nanocircuit addresses specifically the scenario where different quantum chips communicate via polarization-compatible channels, thereby opening new design possibilities for energy-efficient and ultracompact quantum photonic nanocircuits in nanophotonic quantum technologies.