Strong Light–Matter Interactions between Gap Plasmons and Two-Dimensional Excitons under Ambient Conditions in a Deterministic Way
Longlong Yang, Xin Xie, Jingnan Yang, Mengfei Xue, Shiyao Wu, Shan Xiao, Feilong Song, Jianchen Dang, Sibai Sun, Zhanchun Zuo, Jianing Chen, Yuan Huang, Xingjiang Zhou, Kuijuan Jin, Can Wang, Xiulai Xu
Abstract
Strong exciton–plasmon interactions between layered two-dimensional (2D) semiconductors and gap plasmons show a great potential to implement cavity quantum electrodynamics under ambient conditions. However, achieving a robust plasmon–exciton coupling with nanocavities is still very challenging, because the layer area is usually small in the conventional approaches. Here, we report on a robust strong exciton–plasmon coupling between the gap mode of a bowtie and the excitons in MoS 2 layers with gold-assisted mechanical exfoliation and nondestructive wet transfer techniques for a large-area layer. Due to the ultrasmall mode volume and strong in-plane field, the estimated effective exciton number contributing to the coupling is largely reduced. With a corrected exciton transition dipole moment, the exciton numbers are extracted as being 40 for the case of a single layer and 48 for eight layers. Our work paves the way to realize strong coupling with 2D materials with a small number of excitons at room temperature.