Light-induced "plasmonic" properties of organic materials: surface polaritons, bistability and switching waves

Abstract

Purely organic materials with negative and near-zero dielectric permittivity can be easily fabricated, and propa- gation of surface polaritons at the material/air interface was demonstrated. Here we develop a mean- eld theory of nonlinear light-induced plasmonic properties of organic materials. The theory describes both a red shift of the resonance frequency of isolated molecules, according to the Clausius-Mossotti Lorentz-Lorentz mecha- nism, and the wide variations of their spectra related to the aggregation of molecules into J- or H-aggregates. The bistable response of organic materials in the condensed phase has been demonstrated using the electron- vibrational model. We predict the generation of the switching waves, or kinks in the bistable organic thin lms that enable us to observe a bistable behaviour of the surface polaritons at the organic thin lm/dielectric inter- face under the laser irradiation. We present the alternating-sign dependence of the switching wave velocity on pump intensity and discuss a possibility of controlling the polariton propagation by switching waves.