Engineering photon–emitter interfaces with waveguide-coupled quantum dots

  • Datum:

    Freitag, 17.04.2026, 11:00 Uhr

  • Referent:

    Shikai Liu
    Niels Bohr Institut, Quantum Optics and Photonics, Universität Kopenhagen, Dänemark

  • Efficient and deterministic photon–emitter interfaces are a central resource for scalable quantum photonic technologies. Semiconductor quantum dots embedded in nanophotonic waveguides provide a powerful platform where strong light–matter interaction enables coherent control of both photons and spins on a chip. By using waveguide-coupled quantum dots, I will first discuss a Purcell-enhanced neutral exciton as an efficient two-level system to study photon number statistics and its coherence. By exploiting passive photon scattering and single-photon optical nonlinearity, we demonstrate the generation of two-photon energy–time entanglement directly in the transmission port of the waveguide. I will then turn to the negatively charged exciton, which forms a four-level spin system. We observe a spin coupled to a chiral point of the waveguide guided mode. By virtue of magnetic-field-induced state mixing, we realize (i) perfect directional emission and (ii) extremely large chiral cyclicity with upper bound exceeding 4000. Furthermore, chiral coupling allows remote optical control of the spin state via waveguide transmitted Raman process. Finally, I will demonstrate a theoretical protocol for generating remote spin-spin entanglement using our chiral interface. These results highlight how nanophotonic photon–emitter interfaces enable scalable spin–photon networks and quantum non-reciprocal physics.