Experimental Demonstration of Coherent Optical Storage via Precreated Macroscopic Coherence in Eu3+:Y2SiO5

Abstract

We report the first experimental realization of phase-preserving optical storage based on the pre-created long-lived macroscopic coherence (PLMC) protocol in a ${\mathrm{Eu}}^{3+}$:$Y_2{\mathrm{SiO}}_5$ crystal. In contrast to conventional photon-echo schemes that rely on population-based initialization, this protocol exploits a pre-established macroscopic spin coherence as the functional resource for optical storage and retrieval. We successfully observe the photon echo signal governed by the PLMC and achieve a fidelity of coherence preservation of $98.0\pm 1.7\%$ for single-pulse input and $>95\%$ for two-pulse inputs. Crucially, we implement an active noise suppression scheme based on Stark modulation, which effectively eliminates parasitic coherent emissions and enhances the signal-to-noise ratio. These results establish macroscopic coherence as a practical resource for robust coherent optical storage, and provide a pathway toward high-performance quantum memories for scalable quantum communication and network applications.