Enhanced and directional single-photon emission in hyperbolic metamaterials

We propose an approach to enhance and direct the spontaneous emission from isolated emitters embedded inside hyperbolic metamaterials (HMMs) into single-photon beams. The approach rests on collective plasmonic Bloch modes of HMMs, which propagate in highly directional beams called quantum resonance cones. We propose a pumping scheme using the transparency window of the HMM that occurs near the topological transition. Finally, we address the challenge of outcoupling these broadband resonance cones into vacuum using a dielectric bullseye grating. We give a detailed analysis of quenching and design the metamaterial to have a huge Purcell factor in a broad bandwidth in spite of the losses in the metal. Our work should help motivate experiments in the development of single-photon sources for broadband emitters such as nitrogen vacancy centers in diamond.