Open AccessStrong and weak couplings in molecular vibration–plasmon hybrid structures
Author(s) -
Yunwei Chang,
Jie Yao,
Xiaohu Wu,
DaJian Wu,
Xiaojun Liu
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.001479
Subject(s) - plasmon , materials science , grating , coupling (piping) , molecular vibration , surface plasmon resonance , molecular physics , surface plasmon , mode coupling , optics , localized surface plasmon , optoelectronics , nanotechnology , physics , nanoparticle , raman spectroscopy , metallurgy
Molecular vibration-plasmon couplings in a hybrid structure, which are composed of a silver grating filled with polymethyl methacrylate (PMMA) molecules (SG-PMMA), have been investigated theoretically. It is found that the interaction between the vibrational transitions and plasmons can transform from weak coupling into strong coupling by reducing the distance between the elements. When the space between grating elements is large, the localized surface plasmon resonance (LSP) of the silver elements greatly enhances the absorption of the PMMA molecules. As the gap between elements becomes small, the plasmonic nanocavity (NC) mode emerges and couples strongly with the molecular vibrational mode of PMMA. The strong coupling results in two new hybridized modes and the Rabi splitting energy is about 15 meV. Our work provides an effective way to alter the coupling strength of the molecular vibration-plasmon hybrid system and may be beneficial to the further biochemical and biophysical applications.