When a single emitter is excited by two phase-coherent pulses with a time delay, each of the pulses can lead to the emission of a photon pair, thus creating a ``time-bin entangled'' state. Double pair emission can be avoided by initially preparing the emitter in a metastable state. We show how photons from separate emissions can be made indistinguishable, permitting their use for multi-photon interference. Possible realizations are discussed. The method might also allow the direct creation of n-photon entangled states (n>2).
@article{arxiv.quant-ph/0409100,
title = {Creating single time-bin entangled photon pairs},
author = {Christoph Simon and Jean-Philippe Poizat},
journal= {arXiv preprint arXiv:quant-ph/0409100},
year = {2009}
}