Dimensional Crossover of Strong Light–Matter Coupling in a Tunable Microcavity with Layered Perovskites

TzuLing Chen^1*, LingQi Huang¹, ChiaHao Lin¹, ShihChung Chen¹, LiTzu Wang¹, TsungSheng Kao¹, Hyeyoung Ahn¹

¹Department of Photonics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:TzuLing Chen, email:tlc@nycu.edu.tw

Strong coupling between photons and excitons represents a solid-state realization of cavity quantum electrodynamics. We report a tunable free-space microcavity incorporating layered PEA₂PbI₄ and BA–MAPbI₃ perovskites (n = 1, 2) that exhibits a clear anti-crossing behavior with a vacuum Rabi splitting up to 0.10 eV at room temperature. By varying the perovskite layer number, we observe a systematic change in coupling strength, revealing how quantum confinement and dielectric screening govern exciton–photon hybridization. This work provides a controllable platform for studying light–matter coupling beyond the weak regime and illustrates a bridge between condensed-matter polaritonics and AMO cavity QED physics. In future work, this tunable cavity platform will be extended to gas-phase molecular systems to investigate coherent coupling and cavity-modified molecular spectroscopy.

Keywords: Strong light–matter coupling, Vacuum Rabi splitting, Cavity quantum electrodynamics (cQED), Tunable microcavity, Perovskite