One-hour coherent optical storage in an atomic frequency comb memory

Yu Ma,Zong-Quan Zhou,Guang-Can Guo,You-Zhi Ma,Chuan-Feng Li

doi:10.1038/s41467-021-22706-y

Yu Ma, Zong-Quan Zhou + Show 3 more

Open Access

https://doi.org/10.1038/s41467-021-22706-y

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Abstract

Photon loss in optical fibers prevents long-distance distribution of quantum information on the ground. Quantum repeater is proposed to overcome this problem, but the communication distance is still limited so far because of the system complexity of the quantum repeater scheme. Alternative solutions include transportable quantum memory and quantum-memory-equipped satellites, where long-lived optical quantum memories are the key components to realize global quantum communication. However, the longest storage time of the optical memories demonstrated so far is approximately 1 minute. Here, by employing a zero-first-order-Zeeman magnetic field and dynamical decoupling to protect the spin coherence in a solid, we demonstrate coherent storage of light in an atomic frequency comb memory over 1 hour, leading to a promising future for large-scale quantum communication based on long-lived solid-state quantum memories.

Highlights

Photon loss in optical fibers prevents long-distance distribution of quantum information on the ground
Space-borne quantum communication[7,8] and transportable quantum memory[9] can avoid using optical fibers, but optical quantum memories with a lifetime on the order of hours would be essential for extending the communication distance to global scale
In summary, spin-wave atomic frequency comb (AFC) protocol is combined with ZEFOZ technique for the purpose of long-lived quantum storage of photonic qubits

Summary

Introduction

Photon loss in optical fibers prevents long-distance distribution of quantum information on the ground. By employing a zerofirst-order-Zeeman magnetic field and dynamical decoupling to protect the spin coherence in a solid, we demonstrate coherent storage of light in an atomic frequency comb memory over 1 hour, leading to a promising future for large-scale quantum communication based on longlived solid-state quantum memories. With the help of a zero-first-order-Zeeman (ZEFOZ) magnetic field and dynamical decoupling (DD), Zhong et al have reported a 6 h spin coherence lifetime[9] in europium-doped yttrium orthosilicate (Eu3+:Y2SiO5). This long-lived spin coherence is a key resource for constructing quantum memories for global quantum communication. Our work improves the AFC memory time by ~6000 times[22]

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