We report an experiment in which two-photon interference occurs between degenerate single photons that never meet. The two photons travel in opposite directions through our fibre-optic interferometer and interference occurs when the photons reach two different, spatially separated, 2-by-2 couplers at the same time. We show that this experiment is analogous to the conventional Franson-type entanglement experiment where the photons are entangled in position and time. We measure wavefunction overlaps for the two photons as high as 94 ± 3%.
@article{arxiv.0709.0847,
title = {Experimental position-time entanglement with degenerate single photons},
author = {A. J. Bennett and D. G. Gevaux and Z. L. Yuan and A. J. Shields and P. Atkinson and D. A. Ritchie},
journal= {arXiv preprint arXiv:0709.0847},
year = {2008}
}
Comments
Updated to published version, new fig. 4., corrected typos