Demonstration of atomic frequency comb memory for light with spin-wave storage

TL;DR

This paper demonstrates a quantum light storage method using atomic frequency combs in a praseodymium-doped crystal, combining photon echo and spin-wave techniques to achieve on-demand, multi-mode storage suitable for quantum communication.

Contribution

It introduces a novel combination of atomic frequency combs with spin-wave storage for efficient, on-demand quantum light memory in solid-state systems.

Findings

Stored 450 ns optical pulses for up to 20 microseconds

Achieved on-demand retrieval of stored light

Potential for multi-mode quantum memory in quantum networks

Abstract

We present a light-storage experiment in a praseodymium-doped crystal where the light is mapped onto an inhomogeneously broadened optical transition shaped into an atomic frequency comb. After absorption of the light the optical excitation is converted into a spin-wave excitation by a control pulse. A second control pulse reads the memory (on-demand) by reconverting the spin-wave excitation to an optical one, where the comb structure causes a photon-echo type rephasing of the dipole moments and directional retrieval of the light. This combination of photon echo and spin-wave storage allows us to store sub-microsecond (450ns) pulses for up to 20 microseconds. The scheme has a high potential for storing multiple temporal modes in the single photon regime, which is an important resource for future long-distance quantum communication based on quantum repeaters.