Scalable all-solid-state cavity QED on a hybrid quantum dot–lithium niobate platform

All-solid-state cavity quantum electrodynamics (cQED) has drawn significant research interest because of its potential applications in the development of large-scale integrated quantum photonics. However, the long-lasting issues associated with local spectral tuning of the cavity and emitter, in-plane light confinement for efficient light routing, have hindered its on-chip scalable implementations. Here, we overcome these limitations by proposing and demonstrating a hybrid chip-integrated solid-state cQED device with strong in-plane optical mode confinement. The device consists of semiconducting quantum dots (QDs) integrated onto a thin-film lithium niobate (TFLN) microring resonator. By exploring the TFLN’s piezoelectric strain and electro-optic (EO) properties, we have realized local spectral tuning for waveguide-coupled QDs up to 4.82 nm (7.30 meV), enabling on-chip deterministic single-photon emission with a Purcell factor of 3.52. When further combining the independent EO effect-based cavity tuning, we demonstrate an on-chip wavelength-tunable cQED device with Purcell factors over 1.89 in a 0.30 nm (0.45 meV) tuning range, 230 times more than the reported transform-limited linewidth of the QDs emission. The successful demonstration of scalable cQED with circuits-compatible local strain and EO tuning methods opens the avenue to scale up all-solid-state cQED devices in large-scale quantum photonic circuits.