ions*

Atomic defects in solid-state crystals are widely explored as single-photon sources and quantum memories for quantum communications networks based on quantum repeaters. Rare earth ions, in particular Er³⁺, have several unique features including a telecom-band optical transition facilitating long-distance entanglement distribution, and compatibility with a broad range of materials and device structures. I will give an overview of recent progress including fast photon emission from single Er³⁺ ions using silicon nanophotonic cavities [1], single-shot spin readout [2], sub-wavelength addressing based on spectral multiplexing [3] and coherent control of nearby nuclear spins [4]. Through systematic materials exploration, we have significantly extended the spin and optical coherence times of Er³⁺ ions, enabling indistinguishable single-photon emission [5]. I will conclude by discussing ongoing efforts to probe spin-spin interactions, and how these advances may be combined into a practical quantum repeater architecture.

 

[1]       A. M. Dibos, et al, PRL 120, 243601 (2018).

[2]       M. Raha, et al, Nat. Comm. 11, 1605 (2020).

[3]       S. Chen, et al, Science 370, 592 (2020).

[4]       M. T. Uysal, et al, arXiv:2209.05631.

[5]       S. Ourari et al, arXiv: 2301.03564.