We have demonstrated the coherent storage and retrieval of single-photon-level light using the atomic frequency comb protocol in a room temperature rubidium vapour. Velocity-selective optical pumping is used to prepare the comb within the F=2 hyperfine ground state of rubidium, with the spacing between peaks coinciding with half the F=2−F=3 hyperfine splitting of the 52P3/2 excited state. Weak coherent states of average photon number μin=0.083(5) are stored with pre-programmed recall time of 7.5ns with an efficiency of ηAFC=6.59(5)%, while two temporally distinct modes have been stored and recalled with ηAFC=2.6(1)%, allowing for time-bin qubit storage. Finally, the efficiency is observed to be independent of the input pulse polarisation, paving the way for polarisation qubit storage.
@article{arxiv.2510.26870,
title = {Single-Photon-Level Atomic Frequency Comb Storage in Room Temperature Alkali Vapour},
author = {Zakary Schofield and Vanderli Laurindo and Ori Ezrah Mor and Patrick M. Ledingham},
journal= {arXiv preprint arXiv:2510.26870},
year = {2026}
}