Strong Coupling of Ag@Au Hollow Nanocube/J-Aggregate Heterostructures by Absorption Spectra

Achieving strong light–matter interactions at room temperature is critical for the study of quantum optics and advanced quantum applications. In this paper, we constructed a hybrid system composed of Ag@Au hollow nanocubes (HNCs) and J-aggregates to realize the strong plasmon–exciton interaction at room temperature. First, by changing the shell thickness of Ag@Au HNCs, we tuned the localized surface plasmon resonance wavelength (λLSPR) near the exciton peak (575 nm). Furthermore, there is an obvious anticrossing curve in the hybrid structure, and the Rabi splitting is about 179 meV. Finally, the finite-difference time-domain (FDTD) method was utilized to simulate the absorption spectra of the above nanostructure, and the results matched well with the experimental results. We believe that achieving strong interactions lies in decreasing the volume of the local surface plasmon mode of the Ag@Au HNCs, which is approximately 8645 nm3. This work may provide a useful reference value for further exploration of basic optical material research or the development of advanced quantum devices.