Topological edge states vacuum induce photon-exciton strong coupling

Electromagnetic vacuum engineering holds promise for controlling the light-matter interaction in quantum optics. Topological edge states with robustness and anti-scattering are supported in topological photonic structures, and this unique mode is expected to form an electromagnetic vacuum background to study cavity quantum electrodynamics (CQED). Here we embed the resonant dielectric cavity into the electromagnetic vacuum environment formed by topological edge states, achieving photon- exciton strong coupling. For a nanoantenna located in the electromagnetic vacuum background formed by topological edge state, photons scattered to the surroundings can be collected through topological channels, resulting in a loss coefficient that is reduced by a thousand times compared to the vacuum environment, so that the condition 𝑔 > 𝛾, 𝜅 for strong coupling is achieved in topological hybrid systems. Our results provide new ideas for the research of CQED in topological environments.