Hyperbolic metamaterial resonator–antenna scheme for large, broadband emission enhancement and single-photon collection

We model the broadband enhancement of single-photon emission from color centers in silicon-carbide nanocrystals coupled to a planar hyperbolic metamaterial (HMM) resonator. The design is based on positioning the single-photon emitters within the HMM resonator, which is made of a dielectric index-matched with silicon-carbide material. The broadband response results from the successive resonance peaks of the lossy Fabry–Perot structure modes arising within the high-index HMM cavity. To capture this broadband enhancement in the spontaneous emission of the single-photon emitter, we placed a simple gold-based cylindrical antenna on top of the HMM resonator. We analyzed the performance of this HMM-coupled antenna structure in terms of Purcell enhancement, quantum efficiency, collection efficiency, and overall collected photon rate (CPR). For perpendicular dipole orientation relative to the interface, the HMM-coupled antenna resonator leads to a significantly large spontaneous emission enhancement with a Purcell factor of the order of 250, along with a very high average total CPR of about 30 over a broad emission spectrum (700–1000 nm). The peak CPR increases to about 80 at 900 nm, corresponding to the emission of silicon-carbide quantum emitters. This is a state-of-the-art improvement considering previous computational designs have reported a maximum average CPR of 25 across the nitrogen vacancy center emission spectrum, 600–800 nm, with the highest value being about 40 at 650 nm.