title: Near-unity coupling efficiency of a quantum emitter to a photonic crystal waveguide.
abstract: A quantum emitter efficiently coupled to a nanophotonic waveguide constitutes a promising system for the realization of single-photon transistors, quantum-logic gates based on giant single-photon nonlinearities, and high bit-rate deterministic single-photon sources. The key figure of merit for such devices is the β factor, which is the probability for an emitted single photon to be channeled into a desired waveguide mode. We report on the experimental achievement of β=98.43%±0.04% for a quantum dot coupled to a photonic crystal waveguide, corresponding to a single-emitter cooperativity of η=62.7±1.5. This constitutes a nearly ideal photon-matter interface where the quantum dot acts effectively as a 1D "artificial" atom, since it interacts almost exclusively with just a single propagating optical mode. The β factor is found to be remarkably robust to variations in position and emission wavelength of the quantum dots. Our work demonstrates the extraordinary potential of photonic crystal waveguides for highly efficient single-photon generation and on-chip photon-photon interaction.
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Arcari
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: I
authors.initials: I
authors.lastname: Söllner
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Javadi
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Lindskov Hansen
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Mahmoodian
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Thyrrestrup
authors.affiliation: Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors.forename: E H
authors.initials: EH
authors.lastname: Lee
authors.affiliation: Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors.forename: J D
authors.initials: JD
authors.lastname: Song
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Stobbe
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Lodahl