title: All-optical initialization, readout, and coherent preparation of single silicon-vacancy spins in diamond.
abstract: The silicon-vacancy (SiV-) color center in diamond has attracted attention because of its unique optical properties. It exhibits spectral stability and indistinguishability that facilitate efficient generation of photons capable of demonstrating quantum interference. Here we show optical initialization and readout of electronic spin in a single SiV- center with a spin relaxation time of T1=2.4±0.2  ms. Coherent population trapping (CPT) is used to demonstrate coherent preparation of dark superposition states with a spin coherence time of T2⋆=35±3  ns. This is fundamentally limited by orbital relaxation, and an understanding of this process opens the way to extend coherence by engineering interactions with phonons. Hyperfine structure is observed in CPT measurements with the 29Si isotope which allows access to nuclear spin. These results establish the SiV- center as a solid-state spin-photon interface.
authors.affiliation: Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQst), Ulm University, Ulm D-89081, Germany.
authors.forename: Lachlan J
authors.initials: LJ
authors.lastname: Rogers
authors.affiliation: Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQst), Ulm University, Ulm D-89081, Germany.
authors.forename: Kay D
authors.initials: KD
authors.lastname: Jahnke
authors.affiliation: Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQst), Ulm University, Ulm D-89081, Germany.
authors.forename: Mathias H
authors.initials: MH
authors.lastname: Metsch
authors.affiliation: Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Alp
authors.initials: A
authors.lastname: Sipahigil
authors.affiliation: Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQst), Ulm University, Ulm D-89081, Germany.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Binder
authors.affiliation: National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Tokuyuki
authors.initials: T
authors.lastname: Teraji
authors.affiliation: Advanced Materials R & D Laboratories, Sumitomo Electric Industries Limited, Itami, Hyogo 664-0016, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sumiya
authors.affiliation: Research Center for Knowledge Communities, University of Tsukuba, 1-2 Kasuga, Tsukuba, Ibaraki 305-8550, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Isoya
authors.affiliation: Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Mikhail D
authors.initials: MD
authors.lastname: Lukin
authors.affiliation: Electrical & Computer Engineering Department, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Hemmer
authors.affiliation: Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQst), Ulm University, Ulm D-89081, Germany.
authors.forename: Fedor
authors.initials: F
authors.lastname: Jelezko