Low noise single-photon sources are a critical element for quantum technologies. We present a heralded single-photon source with an extremely low level of residual background photons, by implementing low-jitter detectors and electronics and a fast custom-made pulse generator controlling an optical shutter (a LiNbO3 waveguide optical switch) on the output of the source. This source has a second-order autocorrelation g^{(2)}(0)=0.005(7), and an "Output Noise Factor" (defined as the ratio of the number of noise photons to total photons at the source output channel) of 0.25(1)%. These are the best performance characteristics reported to date.
@article{arxiv.1301.2090,
title = {An extremely low-noise heralded single-photon source: a breakthrough for quantum technologies},
author = {G. Brida and I. P. Degiovanni and M. Genovese and F. Piacentini and P. Traina and A. Della Frera and A. Tosi and A. Bahgat Shehata and C. Scarcella and A. Gulinatti and M. Ghioni and S. V. Polyakov and A. Migdall and A. Giudice},
journal= {arXiv preprint arXiv:1301.2090},
year = {2013}
}