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

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.

Nonlocal nonreciprocal optomechanical circulator

“…The parameters used in our protocol can be easily implemented in typical micro- [31,32] or nano- [33,34] optomechanical systems with κ/ω m → 0.1. Low loss remote optical transmission is realized in optical fiber or free space [21,35,36]. Therefore, our protocol provides an executable platform for the implementation of nonlocal and nonreciprocal phonon-photon transmission or control, and eventually provides the basis for applications on quantum information processing or quantum networking.…”

Few-photon storage on a second timescale by electromagnetically induced transparency in a doped solid

“…A lot of effort has been put into increasing the storage efficiency and time [3]. So far, for storage of classical light pulses the largest demonstrated storage efficiency is 92% [4] (though at a short storage time well below 1 ms) and the longest storage time is 53 min [5] (though at a very low efficiency well below 0.1%). Until then, the highest efficiency and the longest storage time of 42 s were achieved with electromagnetically induced transparency (EIT) as the storage protocol [4,6].…”

Topical White Paper: A Case for Quantum Memories in Space

“…This is usually limited by interatomic interactions, thermal effects, external magnetic or electric field noises and can be mitigated with several means. Today, QMs are pushing towards 1 s threshold [9], while classical pulse storage for up to 1 h has been recently demonstrated [10].…”