Nitrogen Vacancy Center Coupled to Hybrid Metal-dielectric Bullseye Nanoantenna for Stable, High Brightness Single Photon Sources

Single photons qubits, emitted from solid-state-based quantum emitters, have proved one of promising physical realizations for quantum technologies and quantum information sciences. However, typical free-standing quantum emitters have isotropic angular emission patterns. This low directivity emission strongly reduces the ability to collect the emitted photons efficiently, especially when using standard, low numerical aperture (NA) optics which is detrimental for practical SPS applications. By using an advanced atomic force microscope (AFM) technique we managed to place a nitrogen-vacancy center (NV center) hosted by nanodiamond at the center of a circular nanoantenna, resulting in a significant enhancement in the directionality. The structure features an emission with divergence angle below 3◦ which is a promising step towards extremely reliable high-efficiency quantum light sources. The concept presented here can be extended to many other types of nano-particle quantum emitters. Such a device offers a promising route for a high brightness, on-chip single photon source operating at room temperature.