Individual Tuning of Directional Emission and Luminance of a Quantum Emitter in a Composite Plasmonic Antenna

High directional emission and high radiative quantum efficiency are strongly needed when moving a single optical nano-emitter (such as a quantum dot) into the practical realm. However, a typical optical nano-emitter struggles to meet the requirements above, which limits its practical applications in next-generation nano-photonic devices such as single-photon sources. Here, to achieve these features simultaneously, we propose and theoretically investigate a composite plasmonic antenna consisting of a hemispherical solid immersion lens (SIL) and a bowtie plasmonic nano-antenna, wherein a high directional emission of 10° and 2.5 × 103 of Purcell factor have both been enabled. Moreover, we find that directionality and the Purcell factor can be manipulated independently in our antenna, which provides a novel platform for the optimization of single-photon sources.