Single-Photon Generation Engineering

Single-photon generation by quantum emitters of specially designed nanostructures can be strongly influenced by the immediate environment, resulting in dramatically enhanced emission rates, along with funneling emission into a well-defined (in terms of propagation direction and polarization state) radiation channel. Single-photon generation engineering thus compels one to search for the configuration incorporating a highly resonant nanocavity coupled to a quantum emitter and to a directional antenna or an optical waveguide. Significant progress has been achieved in understanding physical mechanisms involved in single-photon generation, and impressive experimental demonstrations of ultrabright, polarized, and directional single-photon sources have been reported. At the same time, targeting highly desirable room-temperature generation of indistinguishable single photons, especially when efficiently funneled into single-mode optical waveguides, poses many serious challenges, which are discussed in this Perspective, along with possible ways to tackle these challenges.