Abstract
We propose an all-optical switch that utilizes the technique of storage and retrieval of light pulses. A single photon (probe pulse) switched by another (switching pulse) is feasible, and the on-off ratio can be as large as 10 dB. We have experimentally demonstrated that the energy of the retrieved probe pulse is reduced to about 10% because of the presence of a switching pulse with an energy per unit area of one photon per λ 2 /(2π). The achieved result does not depend on the coupling intensity, the atomic optical density, or the width and shape of the switching pulse. © 2006 Optical Society of America.