title: Generation of single photons with highly tunable wave shape from a cold atomic ensemble.
abstract: The generation of ultra-narrowband, pure and storable single photons with widely tunable wave shape is an enabling step toward hybrid quantum networks requiring interconnection of remote disparate quantum systems. It allows interaction of quantum light with several material systems, including photonic quantum memories, single trapped ions and opto-mechanical systems. Previous approaches have offered a limited tuning range of the photon duration of at most one order of magnitude. Here we report on a heralded single photon source with controllable emission time based on a cold atomic ensemble, which can generate photons with temporal durations varying over three orders of magnitude up to 10 μs without a significant change of the readout efficiency. We prove the nonclassicality of the emitted photons, show that they are emitted in a pure state, and demonstrate that ultra-long photons with nonstandard wave shape can be generated, which are ideally suited for several quantum information tasks.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Pau
authors.initials: P
authors.lastname: Farrera
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Georg
authors.identifier: 0000-0001-6361-4876
authors.initials: G
authors.lastname: Heinze
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Boris
authors.initials: B
authors.lastname: Albrecht
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
authors.forename: Melvyn
authors.initials: M
authors.lastname: Ho
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
authors.forename: Matías
authors.initials: M
authors.lastname: Chávez
authors.affiliation: Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria.|Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Colin
authors.initials: C
authors.lastname: Teo
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sangouard
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.|ICREA-Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain.
authors.forename: Hugues
authors.initials: H
authors.lastname: de Riedmatten