Figure 2.

a) Energy-level diagram under vibrational strong coupling showing the scheme for the Raman scattering from the new vibro-polariton states. b) Schematic description of the FP cavity used in this study composed of two thin Ag mirrors spaced by a PVAc layer. Raman excitation performed using a micro-Raman system with an objective lens. The inset shows the 3D structure of the PVAc monomer emphasizing the C=O bond, the target for VSC, with the exciting and Stokes scattered photons generating Raman scattering from the coupled vibration. |E₁|² (black line) shows qualitatively the intensity distribution of the first cavity mode with which the C=O resonators are coupled.