III-V quantum light source and cavity-QED on Silicon

Non-classical light sources offer a myriad of possibilities in fundamental science and applications including quantum cryptography and quantum lithography. Single photons can encode quantum information and multi-qubit gates in silica waveguide circuits have been used to demonstrate linear optical quantum computing. Scale-up requires miniaturisation of the waveguide circuit and multiple photon sources. Silicon photonics, driven by the incentive of optical interconnects, is a highly promising platform for the passive components, but integrated light sources are limited by silicon's indirect band-gap. III-V semiconductor quantum-dots, on the other hand, are proven quantum emitters. Here we demonstrate single-photon emission from quantum-dots coupled to photonic crystal nanocavities fabricated from III-V material grown directly on silicon substrates. The high quality of the III-V material and photonic structures is emphasized by observation of the strong-coupling regime. This work opens-up the advantages of silicon photonics to the integration and scale-up of solid-state quantum optical systems.