Ultrafast single photon emission from silicon vacancy centers in plasmonic diamond membranes

Ultrabright single-photon sources are essential for increasing the throughput of quantum technologies such as all-photonic quantum computing and quantum key distribution. Silicon vacancy centers in diamonds have emerged as a promising candidate due to their narrow linewidth and environment robustness. Here, we will discuss our recent experiments demonstrating the generation of ultrafast, bright single-photon sources at room temperature. We couple negatively charged silicon vacancy centers in ~10 nm thin membranes of diamond with plasmonic nanogap cavities that are supporting highly-enhanced local electromagnetic fields. We experimentally demonstrate an increase in the radiative spontaneous emission rate (Purcell factor) of over 700-fold resulting in an ultrafast single photon emission lifetime of only 5.5 ps. The enhanced spontaneous emission and collection efficiency also resulted in a photoluminescence enhancement of 3,600-fold and a single-photon generation rate of up to 318 million counts per second (Mcps).