Non-linear Optics with Cold Atoms inside a Hollow Core Photonic Crystal Fiber

The confinement of cold atoms and photons to a diameter comparable to optical wavelength inside a hollow core photonic crystal fiber dramatically enhances the probability of interaction between a single photon and a single atom compared to free space. As a result, an atomic ensemble consisting of a relatively small number of atoms will create a high optical depth medium that will only need a small number of photons to saturate. Furthermore, coherent control techniques such as Electromagnetically Induced Transparency (EIT) can be used to manipulate atom-photon interactions. Here we present an experimental realization of a few-photon switch based on such a system.