Single photon sources are critical for future quantum technologies such as quantum computing, quantum simulators, and unconditionally secure quantum communication.
The recent discovery of quantum emitters in two-dimensional (2D) materials offers a very promising source of single photon sources, with compelling applications for the next generation of integrated photonic devices. In contrast to their 3D counterparts, quantum emitters in amotically thin 2D lattices are not surrounded by any high refractive index medium. This eliminates total internal and Fresnel reflection of emitted single-photons, allowing intrinsically near-ideal extraction efficiency.
Quantum emission has been reported from a diversity of materials, in semiconducting transition metal dichalcogenides (TMDs) and insulating hexagonal boron nitride (hBN). The large band gap of the latter even allows one to resolve the zero phonon line (ZPL) at room temperature and thwarts non-radiative recombination of the localized exciton. Thus, single-photon emitters in hBN have an intrinsically high quantum efficiency which leads to significantly brighter emission. These single-photon sources are suitable for many practical field applications due to their resistance to ionizing radiation, temperature stability over a range spanning 800 K, long-term operation and capabilities for integration with photonic networks, as well as easy handling.
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