Enhanced spontaneous emission of quantum emitter in monolayer and double layer black phosphorus

We theoretically demonstrate that the spontaneous emission rate (SER) of quantum emitter is greatly enhanced in the proximity of single or double layers of black phosphorus (BP). The maximum enhancement factor is on the order of 10⁶, about 3 times larger than that of graphene, due to the large photonic density of states near BP. We also study how the transition frequency, the BP doping level, the distance between emitter and BP, the existence of substrate underneath BP, and the orientation of transition dipole moment influence the SER. With properly designed parameters, both high SER of emitter and low propagation losses of BP surface plasmon polaritons can be achieved in the quantum system, making it a promising candidate for mid-infrared single-photon generation.