title: Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer.
abstract: Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations.
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Coles
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: D M
authors.initials: DM
authors.lastname: Price
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Dixon
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: B
authors.initials: B
authors.lastname: Royall
authors.affiliation: EPSRC National Centre for III-V Technologies, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, UK.
authors.forename: E
authors.initials: E
authors.lastname: Clarke
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: P
authors.initials: P
authors.lastname: Kok
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Skolnick
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Fox
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Hicks Building, Sheffield S3 7RH, UK.
authors.forename: M N
authors.initials: MN
authors.lastname: Makhonin