2023/10/11 by Gupta, Shobhit, Huang, Yizhong, Liu, Shihan +4 · 1 citation
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2310.07120
Optically active solid-state spin qubits thrive as an appealing technology for quantum interconnect and quantum networking, owing to their atomic size, scalable creation, long-lived coherence, and ability to coherently interface with flying qubits. Trivalent erbium dopants in particular emerge as a compelling candidate with their telecom C band emission and shielded 4f intra-shell spin-optical transitions. However, prevailing top-down architecture for rare-earth qubits and devices has not allowed simultaneous long optical and spin coherence necessary for long-distance quantum networks. Here we demonstrate dual erbium telecom spin-photon interfaces in an epitaxial thin-film platform via wafer-scale bottom-up synthesis. Harnessing precise controls over the matrix purity, dopant placement, and symmetry unique to this platform, we simultaneously achieve millisecond erbium spin coherence time and <3 kilohertz optical dephasing rate in an inversion-symmetry protected site and realize both optical and microwave control in a fiber-integrated package for rapid scaling up. These results demonstrate a significant prospect for high-quality rare-earth qubits and quantum memories assembled using a bottom-up method and pave the way for the large-scale development of quantum light-matter interfaces for telecommunication quantum networks.