Vibrational strong coupling modulated by graphene plasmons in deep metal grating structures.

Area of Science:

• Plasmonics
• Nanophotonics
• Quantum Chemistry

Background:

• Vibrational strong coupling (VSC) is crucial for manipulating molecular properties.
• Existing VSC methods often lack spectral tunability and control.
• Graphene plasmonics offers unique opportunities for light-matter interactions.

Purpose of the Study:

• To introduce a novel graphene-integrated deep silver grating for spectrally accessible and controllable VSC.
• To investigate the interaction between graphene plasmon (GP) modes and vibrational-polaritonic states.
• To demonstrate tunability of polaritonic states by modulating graphene properties.

Main Methods:

• Fabrication of a deep silver grating integrated with graphene.
• Characterization of infrared resonances and plasmon modes.
• Spectroscopic analysis of vibrational coupling with PMMA molecules.
• Modulation of polaritonic states via applied chemical potential and graphene layer number.

Main Results:

• The deep silver grating exhibited strong infrared resonances from hybrid magnetic polariton and surface plasmon modes.
• Graphene integration introduced discrete GP modes that coupled with vibrational-polaritonic modes.
• Polaritonic modes split into distinct branches, showing spectral tunability.
• The mixing ratio of grating, molecular, and GP modes was effectively controlled.

Conclusions:

• Graphene-integrated Ag gratings provide a versatile platform for VSC.
• Spectral access and control of polaritonic states are achieved.
• This approach opens possibilities for using polaritonic states in quantum chemistry applications.