, where the high (infinite) frequency permittivity ε ∞ = 3.68 and a reduction parameter f = 0.025 was used to attain parity with experimental results of the vibrational mode coupled plasmon resonance of MIM metasurface. The peak intensity ratio of g k , Lorenz parameter of central frequency ω 0,k , and full width at half maximum (FWHM) of the line width γ k was obtained from experimental IR-RAS spectra of polyimide, shown in Fig. (c) and Fig. as well as summarized in Table .