We demonstrate the generation of rubidium-resonant heralded single photons for quantum memories. Photon pairs are created by cavity-enhanced down-conversion and narrowed in bandwidth to 7 MHz with a novel atom-based filter operating by "interaction-free measurement" principles. At least 94% of the heralded photons are atom-resonant as demonstrated by a direct absorption measurement with rubidium vapor. A heralded auto-correlation measurement shows gc(2)(0)=0.040±0.012, i.e., suppression of multi-photon contributions by a factor of 25 relative to a coherent state. The generated heralded photons can readily be used in quantum memories and quantum networks.
@article{arxiv.1102.0484,
title = {Atom-Resonant Heralded Single Photons by Interaction-Free Measurement},
author = {Florian Wolfgramm and Yannick A. de Icaza Astiz and Federica A. Beduini and Alessandro Cere and Morgan W. Mitchell},
journal= {arXiv preprint arXiv:1102.0484},
year = {2011}
}