Using cavity-enhanced non-degenerate parametric downconversion, we have built a frequency tunable source of heralded single photons with a narrow bandwidth of 8 MHz, making it compatible with atomic quantum memories. The photon state is 70% pure single photon as characterized by a tomographic measurement and reconstruction of the quantum state, revealing a clearly negative Wigner function. Furthermore, it has a spectral brightness of ~1,500 photons/s per MHz bandwidth, making it one of the brightest single photon sources available. We also investigate the correlation function of the down-converted fields using a combination of two very distinct detection methods; photon counting and homodyne measurement.
@article{arxiv.0704.1864,
title = {High purity bright single photon source},
author = {J. S. Neergaard-Nielsen and B. Melholt Nielsen and H. Takahashi and A. I. Vistnes and E. S. Polzik},
journal= {arXiv preprint arXiv:0704.1864},
year = {2009}
}
Comments
9 pages, 4 figures; minor changes, added reference