Semiconductor Quantum Dots for Integrated Quantum Photonics

Quantum mechanics promises to have a strong impact on many aspects of research and technology, improving classical analogues via purely quantum effects. A large variety of tasks are currently under investigation, for example, the implementation of quantum computing, sensing, metrology, and communication. From a general perspective, in a similar way as classical computing benefited by the reduction of the device footprint, enabling the realization of highly complex chips, a range of quantum applications will sensibly improve thanks to the successful realization of on-chip quantum photonics. Conversely to bulky table-top experiments, it would be very advantageous to transfer all required functionalities on the same quantum photonic chip. The key elements for quantum photonic circuits are on-demand nonclassical light sources, a versatile photonic logic, the ability to store quantum information, and highly efficient detectors, directly integrated on-chip. Among several systems capable of the efficient generation of single- and indistinguishable photons, quantum dots are rapidly establishing as one of the most appealing candidates. This paper reviews the recent progress in the on-chip integration of quantum-dot-based nonclassical light sources as well as in the development of the main building blocks, either integrated monolithically or hybridly on a compact and scalable platform.