Figure 3.

Extinction spectra of a strongly coupled array simulated and measured at different angles of incidence. The simulations are multiplied by 0.4 to facilitate the comparison. (a) Comparison between simulated and measured extinction for p-polarized light. (b) Comparison between simulated and measured extinction for s-polarized light. Polaritons are clearly visible for both polarizations around the C=O bond wavenumber (1732 cm^–1) indicated by the red dashed line. (c) Simulated (left) and measured (right) spectra for different angles of incidence and p-polarized light. These spectra have been displaced vertically for clarity. The red dotted curve represents the spectral position of the C=O vibration. The black dotted lines are a guide to the eyes for the lower and upper polaritons. The feature in all spectra around 2400 cm^–1 is the CO₂ signature peak in the mIR. (d) Simulated (left) and measured (right) spectra for different angles of incidence and s-polarized light.