Spatial and polarization-resolved exciton-photon coupling in quasi-whispering-gallery mode ZnO microrod cavity

Whisper gallery mode (WGM) resonances and the coupling of excitons and WGMs are measured from ZnO microrod cavity in the visible and ultraviolet spectral ranges. The coupling of excitons and WGMs leads to split modes which exhibit a clear spatial dependence due to the uneven field distribution of WGM on ZnO microrod surface. Polarization dependent behavior together with a blueshift of the upper polariton branch mode are observed owing to the transition polarization of different types of excitons in the ZnO microcavity. Numerical simulations are carried out using finite element method to support the experimental results. This work reveals the spatial and polarization dependent exciton-photon coupling in a ZnO microrod which implies promising applications in photonic polariton field ranging from ultraviolet lasers, high-sensitivity detectors to optoelectronic devices

Automated summary

In this study, the coupling of excitons and Whisper Gallery Mode (WGM) resonances in a ZnO microrod cavity was measured in the visible and ultraviolet spectral ranges. The results showed that the exciton-WGM coupling led to split modes with clear spatial dependence. The polarization dependent behavior and the blueshift of the upper polariton branch mode were observed, indicating the transition polarization of different types of excitons in the ZnO microcavity. Numerical simulations supported the experimental findings. This research reveals the spatial and polarization dependent exciton-photon coupling in ZnO microrods, suggesting potential applications in the field of photonic polaritons ranging from ultraviolet lasers to optoelectronic devices.