A major challenge in quantum optics and quantum information technology is to enhance the interaction between single photons and single quantum emitters.Highly engineered optical cavities are generally implemented requiring nanoscale fabrication precision. We demonstrate a fundamentally different approach in which disorder is used as a resource rather than a nuisance. We generate strongly The interaction between a single photon and a single quantized emitter is the core of cavity quantum electrodynamics (QED) and constitutes a node in a quantum information network (1,2). So far, cavity QED experiments have been realized with a wide range of two-level systems including atoms (3), ions (4), Cooper-pair boxes (5), and semiconductor quantum dots (6-8) coupled to photons confined in a cavity.

Self-assembled, epitaxially grown InAs/GaAs quantum dots (QDs) are promising semiconductor quantum emitters that can be integrated on a chip for a variety of photonic quantum information science applications. However, self-assembled growth results in an essentially random in-plane spatial distribution of QDs, presenting a challenge in creating devices that exploit the strong interaction of single QDs with highly confined optical modes. Here, we present a photoluminescence imaging approach for locating single QDs with respect to alignment features with an average position uncertainty <30 nm (<10 nm when using a solid-immersion lens), which represents an enabling technology for the creation of optimized single QD devices. To that end, we create QD single-photon sources, based on a circular Bragg grating geometry, that simultaneously exhibit high collection efficiency (48%±5% into a 0.4 numerical aperture lens, close to the theoretically predicted value of 50%), low multiphoton probability (g(2)(0) <1%), and a significant Purcell enhancement factor (≈3).