title: Quantum optics. All-optical routing of single photons by a one-atom switch controlled by a single photon.
abstract: The prospect of quantum networks, 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. We realized 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 atom coupled to a fiber-coupled, chip-based microresonator. A single reflected control photon toggles the switch from high reflection (R ~ 65%) to high transmission (T ~ 90%), with an average of ~1.5 control photons per switching event (~3, including linear losses). No additional control fields are required. The control and target photons are both in-fiber and practically identical, making this scheme compatible with scalable architectures for quantum information processing.
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Itay
authors.initials: I
authors.lastname: Shomroni
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Serge
authors.initials: S
authors.lastname: Rosenblum
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yulia
authors.initials: Y
authors.lastname: Lovsky
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Orel
authors.initials: O
authors.lastname: Bechler
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Guendelman
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel. barak.dayan@weizmann.ac.il.
authors.forename: Barak
authors.initials: B
authors.lastname: Dayan