Efficient Solid-State Single-Photon Sources Based on Diamond Colour Centers Coupled to Plasmonic Bullseye Resonators

Summary form only given. Future applications in applied physical and quantum information science rely on the efficient and deterministic creation of single photons at a high rate. Creating such a single-photon source requires two key components: A quantum light source emitting single photons and a physical structure, which facilitates the efficient collection of the emitted photons. A very promising candidate for a stable optical quantum emitter are defect centers in diamond as they emit single photons even at room temperature. However, as the emission of diamond defect centers behaves similar to a point dipole, standard photoluminescence techniques alone cannot achieve high collection efficiencies. By using nanodiamonds, light losses due to total internal reflection at the diamond surface can be circumvented. Additionally, the small size of the solid-state emitter offers the possibility to incorporate the nanodiamond into suitable photonic or plasmonic structures. Therefore, our interest lies in the coupling of diamond colour centers to suitable plasmonic structures enabling the redirection and, therefore, efficient collection of the emitted light. For this purpose, we produce plasmonic bullseye resonators made of aluminium using an electron beam lithography based fabrication technique (compare figure la for an SEM image of a fabricated structure). Due to their regular concentric geometry, such a structure behaves as a plasmonic phase array for light and facilitates the redirection of light to small emission angles. In combination dielectric with a reflecting dielectric mirror at substrate the bottom, one can therefore expect large collection efficiencies even for small NA optics. Figure lb illustrates the combination of such a nanodiamond in a cross-sectional view.