All-optical routing of single photons by a one-atom switch controlled by a single photon

Abstract

Routing one photon with a few others Single particles of light, photons, are ideal carriers of quantum information because they can travel far and fast and don't interact much with each other. However, this behavior has hampered attempts to control the propagation of single photons using all-optical setups. Shomroni et al. coupled a trapped atom to an optic fiber. That allowed them to control the polarization and propagation direction of a single photon in the fiber by controlling the atom's state (see the Perspective by Rempe). Because a faint pulse containing between 1.5 and 3 photons can switch the atom's state, the scheme provides a route to develop all-optical quantum networks. Science , this issue p. 903 ; see also p. 871