Plasmon Enhanced Quantum Properties of Single Photon Emitters with Hybrid Hexagonal Boron Nitride Silver Nanocube Systems

Abstract: Hexagonal boron nitride (hBN) has emerged as a promising ultrathin host of single photon emitters (SPEs) with favorable quantum properties at room temperature, making it a highly desirable element for integrated quantum photonic networks. One major challenge of using these SPEs in such applications is their low quantum efficiency. Recent studies have reported an improvement in quantum efficiency by up to two orders of magnitude when integrating an ensemble of emitters such as boron vacancy defects in multilayered hBN flakes embedded within metallic nanocavities. However, these experiments have not been extended to SPEs and are mainly focused on multiphoton effects. Here, we study the quantum single photon properties of hybrid nanophotonic structures composed of SPEs created in ultrathin hBN flakes coupled with plasmonic silver nanocubes. We demonstrate > 200% plasmonic enhancement of the SPE properties, manifested by a strong increase in the SPE fluorescence. Such enhancement is explained by rigorous numerical simulations where the hBN flake is in direct contact with the Ag nanocubes that cause the plasmonic effects. The presented strong and fast single photon emission obtained at room-temperature with a compact hybrid nanophotonic platform can be very useful to various emerging applications in quantum optical communications and computing.