Abstract

Semiconductor quantum dots have excellent optical performance dramatically in recent years, and today a clear pathway is laid out for constructing a deterministic and coherent photon-emitter interface by embedding quantum dots in photonic nanostructures [1]. Such an interface can be employed as an on-demand single-photon source, but more generally enables deterministic quantum gates. We review the recent experimental progress on quantum dots coupled to nanophotonic waveguides including the internal single-photon coupling efficiency [2], coherence [3], and transfer efficiency to an optical fiber [4]. Currently, the first commercial products based on this technology are being brought to the market [5]. Finally the fundamental decoherence processes of a quantum dot single-photon source are discussed [6]. [1] Lodahl et al., Rev. Mod. Phys. 87, 347 (2015). [2] Arcari et al., Phys. Rev. Lett. 113, 093603 (2014). [3] Kirsanske et al., submitted, arXiv:1701.08131 [4] Daveau et al., Optica 4, 178 (2017). [5] Single-photon chip technology is currently commercialized by the company Sparrow Quantum A/S, www.sparrowquantum.com [6] Tighineanu et al., arXiv:1702.04812