Abstract: We implement permanent spectral tuning to bring lifetime-limited emitters into collective resonance within an integrated photonic cavity. This addresses a fundamental challenge in solid-state cavity QED: combining multiple coherent quantum emitters with scalable nanophotonics. Our hybrid approach decouples emitter synthesis from nanophotonic fabrication using straightforward techniques that make cavity QED broadly accessible. Building on our previous demonstration of superradiance and subradiance in pairs of molecules [1], we now couple several coherent emitters to a single cavity mode through high doping densities. Optically-induced frequency shifting provides long-lived spectral control, allowing us to tune multiple molecules into resonance and demonstrate controlled formation of collective quantum states [2]. This establishes a scalable platform for many-body cavity QED and opens pathways toward chemically-designed quantum systems where optical properties are engineered through synthetic chemistry. We will also report on progress in our ultracold Li-Cs experiment, including cooling with the narrow 5D transition [3].
[1] C. Lange, E. Daggett, V. Walther, L. Huang, and J.D. Hood, Nature Physics (2024)
[2] C. Lange et al., arXiv:2406.01917 (2025)
[3] Blodgett et al., arXiv :2505.10540 (2025)