Chasing Vibro-Polariton Fingerprints in Infrared and Raman Spectra Using Surface Lattice Resonances on Extended Metasurfaces

We present an experimental investigation of vibrational strongcoupling of C???O bonds in poly(methyl methacrylate) to surface latticeresonances (SLRs) on arrays of gold particles in infrared and Raman spectra.SLRs are generated from the enhanced radiative coupling of localized resonancesin single particles by diffraction in the array. Compared to previous studies inFabry-Perot cavities, particle arrays provide a fully open system that easily coupleswith external radiation while having largefield confinement close to the array. Wecontrol the coupling by tuning the period of the array, as evidenced by the splittingof the C???O vibration resonance in the lower and upper vibro-polaritons of the IRextinction spectra. Despite clear evidence of vibrational strong coupling in IRtransmission spectra, both Raman spectroscopy and micro-Raman mapping do notshow any polariton signatures. Our results suggest that the search for vibrational strong coupling in Raman spectra may needalternative cavity designs or a different experimental approach.

Automated summary

This study investigates vibrational strong coupling of C-O bonds in poly(methyl methacrylate) to surface lattice resonances (SLRs) on gold particle arrays in infrared and Raman spectra. While evidence of strong coupling was seen in IR transmission spectra, it was not observed in Raman spectroscopy. Further research may be needed to find vibrational strong coupling in Raman spectra, possibly requiring alternative cavity designs or experimental approaches.