Slow-light-enhanced Atomic Frequency Comb Quantum Memory in Stoichiometric EuCl$_3 \cdot$ 6D$_2$O

Abstract:Rare-earth-doped crystals are promising candidates for quantum storage, yet their performance in free-space configurations is fundamentally restricted by low optical depth. Here, we demonstrate high-efficiency quantum storage in a stoichiometric EuCl$_3 \cdot$ 6D$_2$O crystal, which intrinsically provides high optical density without the complexity of cavity implementation. We show that in this high-density regime, the system exhibits significant slow-light-like effects, including dispersion-induced echo delays and finesse-dependent echo intensity modulation. We develop a unified theoretical framework showing how absorption and dispersion work in concert to mediate echo generation. We achieve storage efficiencies of 42.9% for classical light and 34.4% for weak coherent pulses, alongside 90% efficiency for slow-light storage. These findings validate EuCl$_3 \cdot$ 6D$_2$O as a robust platform, establishing a viable pathway for scalable solid-state quantum memory.

arXiv:2607.28060 [quant-ph]

(or arXiv:2607.28060v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2607.28060 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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