Multimode capacity of atomic-frequency comb quantum memories

Antonio Ortu, Jelena V. Rakonjac, Adrian Holzäpfel, Alessandro Seri, Samuele Grandi*, Margherita Mazzera, Hugues de Riedmatten, Mikael Afzelius

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
28 Downloads (Pure)


Ensemble-based quantum memories are key to developing multiplexed quantum repeaters, able to overcome the intrinsic rate limitation imposed by finite communication times over long distances. Rare-earth ion doped crystals are main candidates for highly multimode quantum memories, where time, frequency and spatial multiplexing can be exploited to store multiple modes. In this context the atomic frequency comb (AFC) quantum memory provides large temporal multimode capacity, which can readily be combined with multiplexing in frequency and space. In this article, we derive theoretical formulas for quantifying the temporal multimode capacity of AFC-based memories, for both optical memories with fixed storage time and spin-wave memories with longer storage times and on-demand read out. The temporal multimode capacity is expressed in key memory parameters, such as AFC bandwidth, fixed-delay storage time, memory efficiency, and control field Rabi frequency. Current experiments in europium- and praseodymium-doped Y2SiO5 are analyzed within this theoretical framework, which is also tested with newly acquired data, as prospects for higher temporal capacity in these materials are considered. In addition we consider the possibility of spectral and spatial multiplexing to further increase the mode capacity, with examples given for praseodymium doped Y2SiO5.

Original languageEnglish
Article number035024
JournalQuantum Science and Technology
Issue number3
Early online date17 Jun 2022
Publication statusPublished - Jul 2022


  • atomic frequency comb
  • multimode quantum memory
  • rare-earth ion doped crystals

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science (miscellaneous)
  • Physics and Astronomy (miscellaneous)
  • Electrical and Electronic Engineering


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