Strong Plasmon-Exciton Interactions on Nanoantenna Array-Monolayer WS2 Hybrid System

Strong plasmon-exciton interactions in monolayer transition-metal dichalcogenides (TMDs) is emerging as a promising material platform for light emissions, nonlinear optics, and quantum communications, and their realizations require highly localized electric fields parallel to the transition dipole moment of TMD excitons. Here, a systematic study of light-matter interaction in planar dimer nanoantenna of nanoscale gaps coupled with monolayer WS2 is presented, where the effects of the local field enhancement and spatial mode overlap in the plasmon-exciton coupling strength are experimentally investigated. Importantly, anticrossing behaviors in the strong coupling regime with a Rabi splitting of omega = 118 meV for gold bowtie antennas with 7 nm gaps and omega = 138 meV for gold dimer arrays with 10 nm gaps are demonstrated.