Electrically Driven Quantum Light Sources

Typical applications of quantum light require optical sources which generate either individual photons or entangled (correlated) photons. For the sake of practicality and scalability, these quantum sources should be easily produced, operate at room temperature, and be electrically excited and controlled. Here, recent research on quantum sources obtained from electrically driven (ED) devices constructed from p–n junctions integrated in planar optical cavities, micropillars, nanowires, photonic crystals, and active plasmonic elements is reviewed. Single‐photon and entangled‐photon sources are distinguished by their different roles in the development of either quantum cryptography or quantum computing protocols, and the different types of devices used to produce them are highlighted, with a focus on their spectral emission, brightness, and conditions of operation. Achievements to date are summarized and compared with prerequisites for the practical use of these sources. Important recent results that could provide future novel quantum sources are also in focus, where more practical requirements could be addressed by the judicious engineering of materials and careful device design.