Zero-Dimensional Organic Exciton-Polaritons in Tunable Coupled Gaussian Defect Microcavities at Room Temperature

We demonstrate strong light-matter interaction at ambient conditions between a ladder-type conjugated polymer and the individual modes of a vertical microcavity with tunable resonance frequencies. Zero-dimensional wavelength-scale confinement for the polaritons is achieved through a sub-micrometer-sized Gaussian defect, resulting in a vacuum Rabi splitting of the polariton branches of 2g = 166 meV. By placing a second Gaussian defect nearby, we create a polaritonic molecule with a tunnel coupling strength of up to 2J ≈ 50 meV. This platform enables the creation of tailor-made potential landscapes with wavelength-scale dimensions and tunable coupling strengths beyond the thermal energy, opening a route toward room-temperature polariton-based quantum simulators.