It is shown that parametric downconversion, with a short-duration pump pulse and a long nonlinear crystal that is appropriately phase matched, can produce a frequency-entangled biphoton state whose individual photons are coincident in frequency. Quantum interference experiments which distinguish this state from the familiar time-coincident biphoton state are described.
@article{arxiv.quant-ph/0109135,
title = {Generating Entangled Two-Photon States with Coincident Frequencies},
author = {Vittorio Giovannetti and Lorenzo Maccone and Jeffrey H. Shapiro and Franco N. C. Wong},
journal= {arXiv preprint arXiv:quant-ph/0109135},
year = {2009}
}
Comments
Revised version (a typo was corrected) as published on PRL