Resonant interaction of molecular vibrations and surface plasmon polaritons: The weak coupling regime

摘要

Adjusting the free-electron concentration, the surface plasmon frequency ofthe semiconductor ZnOGa is tuned into resonance with the molecular vibrationsof the n-alkane tetracontane. Closed molecular films deposited on thesemiconductor's surface in the monolayer regime generate distinct signatures intotal-attenuated-reflection spectra at the frequencies of the symmetric andasymmetric stretching vibrations of the CH2 group. Their line shape undergoesprofound changes from absorptive to dispersive and even anti-resonance behaviorwhen moving along the surface- plasmon dispersion by the angel of incidence. Wedemonstrate that this line shape diversity results from a phase-sensitiveperturbation of the surface-plasmon-polariton generation at the molecule/metalinterface.