Storage and recall of weak coherent optical pulses with an efficiency of 25%

TL;DR

This paper demonstrates a quantum memory for weak coherent optical pulses with 25% efficiency using an atomic frequency comb in a Pr:YSiO crystal, showing potential for improved quantum information storage.

Contribution

The study introduces a high-efficiency quantum memory scheme employing AFC in a rare-earth crystal, achieving 25% storage and retrieval efficiency for weak coherent pulses.

Findings

Achieved 25% storage and retrieval efficiency.

Proved coherence preservation via interference experiments.

Potential for higher efficiency with backward retrieval.

Abstract

We demonstrate experimentally a quantum memory scheme for the storage of weak coherent light pulses in an inhomogeneously broadened optical transition in a Pr^{3+}: YSO crystal at 2.1 K. Precise optical pumping using a frequency stable (about 1kHz linewidth) laser is employed to create a highly controllable Atomic Frequency Comb (AFC) structure. We report single photon storage and retrieval efficiencies of 25%, based on coherent photon echo type re-emission in the forward direction. The coherence property of the quantum memory is proved through interference between a super Gaussian pulse and the emitted echo. Backward retrieval of the photon echo emission has potential for increasing storage and recall efficiency.