Long-Lived Solid-State Optical Memory for High-Rate Quantum Repeaters
We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters. Triggered by this conclusion, we investigate the 795.325 nm ³H₆ ↔ ³H₄ transition of T_m:Y₃Ga₅O₁₂ (Tm:YGG). Most importantly, we find that the optical coherence time can reach 1.1 ms, and, using laser pulses, we demonstrate optical storage based on the atomic frequency comb protocol during up to 100 μs as well as a memory decay time T_m of 13.1 μs. Possibilities of how to narrow the gap between the measured value of T_m and its maximum of 275 μs are discussed. In addition, we demonstrate multiplexed storage, including with feed-forward selection, shifting and filtering of spectral modes, as well as quantum state storage using members of nonclassical photon pairs. Our results show the potential of Tm:YGG for creating multiplexed quantum memories with long optical storage times, and open the path to repeater-based quantum networks with high entanglement distribution rates.
© 2021 American Physical Society. (Received 4 June 2021; accepted 20 October 2021; published 22 November 2021) The authors thank M. Grimau Puigibert, T. Chakraborty, and O. P. Casas for experimental help and M. Afzelius for discussions. We acknowledge funding through the Netherlands Organization for Scientific Research, the European Unions Horizon 2020 Research and Innovation Program under Grant Agreement No. 820445 and Project Name Quantum Internet Alliance, Alberta Innovates Technology Futures, the National Sciences and Engineering Research Council of Canada, the Alberta Ministry of Jobs, Economy and Innovation's Major Innovation Fund Project on Quantum Technologies. Furthermore, W. T. acknowledges funding as a Senior Fellow of the Canadian Institute for Advanced Research (CIFAR). This material is based in part on research at Montana State University sponsored by Air Force Research Laboratory under Agreement No. FA8750-20-1-1004.
Submitted - 2106.02530.pdf
Published - PhysRevLett.127.220502.pdf
Supplemental Material - Supplemental_3.pdf