Tuning surface plasmon-exciton coupling via thickness controlling of excitonic layer

¹ School of Information & Electric Engineering, Zhejiang University City College - Hangzhou 310015, China
² State Key lab of Silicon Materials, Zhejiang University - Hangzhou 310027, China
³ Department of Physics, Zhejiang University - Hangzhou 310028, China
⁴ Department of Science, Zhijiang College of Zhejiang University of Technology - Shaoxing 312030, China
⁵ Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences - Hangzhou 310024, China

^(a) big@zucc.edu.cn (corresponding author)

Received: 22 May 2021
Accepted: 7 September 2021

Abstract

We present the Rabi energy tuning effects in strong coupling effects between surface plasmon (SP) and exciton in the Kretschmann-Raether configuration by varying excitonic layer thickness. Both experimental results and theoretical calculations indicate that the anticross-like dispersion relation comes from the rapid change of permittivity near the exciton state and can be attributed to the strong coupling between SP and exciton. Our findings reveal that the excitonic layer plays a key role in the SP-exciton coupling. The increase of the excitonic layer will not only enlarge the Rabi splitting energy, but also cause the redshift of SP dispersion relation. Thus to fulfill the coupling condition, there is a critical thickness of the excitonic layer at specific incident angle . With the increase of excitonic layer thickness, the Rabi energy increases monotonously and tends to saturate. Our findings will be beneficial for the better understanding of SP-exciton strong coupling in KR configuration and can be useful in tuning the Rabi energy and resonant conditions according to practical applications.