Plasmonic grating for circularly polarized outcoupling of waveguide-enhanced spontaneous emission

Abstract

Plasmonic metasurfaces form a convenient platform for light manipulation at the nanoscale due to their specific localized surface plasmons. Even despite high intrinsic Joule losses, plasmonic nanoparticles are very effective for light manipulation. Here, we show the lattice of plasmonic nanoparticles onto a dielectric waveguide that efficiently couples oppositely propagating guided modes to circularly polarized light beams of different handedness. We demonstrate 80% degree of circular polarization for the out-coupled emission of GaAs-waveguide-embedded quantum dots. The results allow us to consider the lattice as a circular-polarization-controlled grating coupler and make this structure prospective for further implementation as an efficient coupling interface for integrated devices.