Molecular plasmonics: the role of ro-vibrational molecular states in exciton-plasmon materials under strong coupling conditions

摘要

We extend the model of exciton-plasmon materials to include a ro-vibrationalstructure of molecules using wave-packet propagations on electronic potentialenergy surfaces. The new model replaces conventional two-level emitters withmore complex molecules allowing to examine the influence of alignment andvibrational dynamics on strong coupling with surface plasmon-polaritons. Weapply the model to a hybrid system comprising a thin layer of molecules placedon top of a periodic array of slits. Rigorous simulations are performed for twotypes of molecular systems described by vibrational bound-bound andbound-continuum electronic transitions. Calculations reveal new features intransmission, reflection and absorption spectra including the observation ofsignificantly higher values of the Rabi splitting and vibrational patternsclearly seen in the corresponding spectra. We also examine the influence ofanisotropic initial conditions on optical properties of hybrid materialsdemonstrating that the optical response of the system is significantly affectedby an initial pre-alignment of the molecules. Our work demonstrates thatpre-aligned molecules could serve as an efficient probe for the sub-diffractioncharacterization of the near-field near metal interfaces.