While being optimally compensated for spatial phase variations, the two-photon state produced by the two-crystal emission exhibits spatial and spectral decoherence off the central emission modes. In this paper, we present an experimentally convenient method to optimize the ultra-wide spatial and spectral windows; allowing the minimum spatial-spectral decoherence for a required two-photon flux.
@article{arxiv.1609.03884,
title = {Optimal Ultra-wide Spatial-Spectral Windows for Hyperentangled Two-photon Emission},
author = {S. F. Hegazy and J. El-Azab and Y. A. Badr and S. S. A. Obayya},
journal= {arXiv preprint arXiv:1609.03884},
year = {2016}
}