Spontaneous Raman emission in atomic gases provides an attractive source of photon pairs with a controllable delay. We show how this technique can be implemented in solid state systems by appropriately shaping the inhomogeneous broadening. Our proposal is eminently feasible with current technology and provides a realistic solution to entangle remote rare-earth doped solids in a heralded way.
@article{arxiv.1101.6005,
title = {A photon-pair source with controllable delay based on shaped inhomogeneous broadening of rare-earth doped solids},
author = {Pavel Sekatski and Nicolas Sangouard and Nicolas Gisin and Hugues de Riedmatten and Mikael Afzelius},
journal= {arXiv preprint arXiv:1101.6005},
year = {2011}
}