Ultrafast manipulation of strong coupling in metal-molecular aggregate hybrid nanostructures

Abstract

We demonstrate an ultrafast manipulation of the Rabi splitting energy ΩR in a metal-molecular aggregate hybrid nanostructure. Femtosecond excitation drastically alters the optical properties of a model system formed by coating a gold nanoslit array with a thin J-aggregated dye layer. Controlled and reversible transient switching from strong (ΩR ≃ 55 meV) to weak (ΩR ≈ 0) coupling on a sub-ps time scale is directly evidenced by mapping the nonequilibrium dispersion relations of the coupled excitations. Such a strong, externally controllable coupling of excitons and surface plasmon polaritons is of considerable interest for ultrafast all-optical switching applications in nanoscale plasmonic circuits. © 2010 American Chemical Society.