We demonstrate a fiber-optical switch that is activated at tiny energies corresponding to few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic-crystal fiber and using quantum optical techniques for generating slow light propagation and large nonlinear interaction between light beams.
@article{arxiv.0901.0336,
title = {Efficient all-optical switching using slow light within a hollow fiber},
author = {M. Bajcsy and S. Hofferberth and V. Balic and T. Peyronel and M. Hafezi and A. S. Zibrov and V. Vuletic and M. D. Lukin},
journal= {arXiv preprint arXiv:0901.0336},
year = {2015}
}