He Zijian, Han Xiaobo, Zhang Liyu, Yang Jiaxing, Chen Shuzheng, Xiao Siyi, Ji Shuai, Wang Kai, Lu Peixiang
Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China.
Nano Lett. 2025 Jul 2;25(26):10556-10562. doi: 10.1021/acs.nanolett.5c02217. Epub 2025 Jun 23.
All-dielectric metasurfaces have emerged as promising platforms for studying strong coupling due to their low absorptive losses and diverse resonance modes. However, previous works have primarily focused on all-dielectric metasurfaces with electric/magnetic dipole (ED/MD) modes, while higher-order multipoles, such as electric quadrupole (EQ), have not been fully explored. Here, we report on an EQ-involved strong coupling based on the monolayer WS integrated all-dielectric metasurfaces. By precisely tuning the EQ modes to be spectrally overlapped with the A exciton resonance of WS (at 614 nm), angle-resolved transmission spectra show a clear anticrossing behavior with a 31.7 meV Rabi splitting. EQ modes feature spatially varying field gradients and strong in-plane electric fields at the interface, thus increasing the coupling efficiency with two-dimensional materials. This work presents a novel strategy for developing low-loss, compact polaritonic devices, contributing to a deeper understanding of the strong coupling mechanisms between higher-order multipoles and excitons.
全介质超表面因其低吸收损耗和多样的共振模式，已成为研究强耦合的有前景的平台。然而，以往的工作主要集中在具有电/磁偶极（ED/MD）模式的全介质超表面上，而诸如电四极（EQ）等高阶多极子尚未得到充分探索。在此，我们报道了基于单层WS集成全介质超表面的涉及EQ的强耦合。通过精确调整EQ模式使其在光谱上与WS的A激子共振（在614nm处）重叠，角分辨透射光谱显示出清晰的反交叉行为，拉比分裂为31.7meV。EQ模式在界面处具有空间变化的场梯度和强面内电场，从而提高了与二维材料的耦合效率。这项工作提出了一种开发低损耗、紧凑型极化子器件的新策略，有助于更深入地理解高阶多极子与激子之间的强耦合机制。
