All-optical routing of single photons by a single atom

The prospect of quantum networks [1], in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons.

I will present our recent demonstration [2] of the basic unit of such a photonic circuit: a single-photon activated switch, capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single ⁸⁷Rb atom in a three-level lambda configuration [3,4], coupled to a chip-based, fiber-coupled microsphere resonator, and is completely all-optical, requiring no other fields besides the in-fiber single-photon pulses.

[1] H. J. Kimble, "The quantum internet." Nature 453, 1023 (2008).

[2] I. Shomroni, S. Rosenblum, Y. Lovsky, O. Bechler, G. Guendelman, and B. Dayan. "All-optical routing of single photons by a one-atom switch controlled by a single photon." Science 345, 903 (2014).

[3] D. Pinotsi, and A. Imamoglu. "Single photon absorption by a single quantum emitter." Phys. Rev. Lett. 100, 093603 (2008).

[4] S. Rosenblum, S. Parkins, and B. Dayan. “Photon routing in cavity QED: Beyond the fundamental limit of photon blockade.” Physical Review A 84, 033854 (2011).