Quantum Nano-Jewelry: Plasmonic Addressing of Single-Photon Emitters in High-Quality Diamond Nanostructures

The negatively charged silicon-vacancy center (SiV) in diamond is a potential high-quality single-photon source for quantum information processing and quantum electrodynamics applications[1]. The dipole moment of the SiV is aligned predominantly along its symmetry axis which connects the interstitial silicon atom and the two adjacent vacancies with 4 possible <;111>-orientations. Since the SiV addressing is done optically the demand for efficient excitation and optical out-coupling is essential for realizing high-quality single-photon sources. In addition to relatively low extraction efficiency when embedded in bulk diamond, attributed to total internal reflection, in a <;100>-oriented diamond, which is commonly used, each SiV possesses a dominant dipole component aligned normal to the diamond-air interface. Thus, resulting in a poor optical out-coupling since a dipole radiates primarily into the plane orthogonal to its axis.