title: Large optical-frequency shift of molecular radiation via coherent coupling to an off-resonance plasmon.
abstract: We demonstrate coherent optical coupling between molecular and plasmon resonances that are well separated in energy. In the presence of metallic nanoparticles, the second harmonic spectrum of organic dyes no longer peaks at the absorption wavelength but is instead blueshifted by 25 nm towards the localized plasmon resonance. The phase of the light generated by the dyes displays a large modulation across the plasmon resonance and no change across the molecular one. The second harmonic signal contributed by the nanoparticles, which is peaked at the plasmon frequency when no molecules are present, similarly displays a shift towards the molecular resonance in their presence. A model based on the interplay of the nonlinear optical near fields is able to account for these observations.
authors: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Barcelona, Spain. roberto.macovez@upc.edu
authors: Roberto
authors: R
authors: Macovez
authors: Marina
authors: M
authors: Mariano
authors: Sergio
authors: S
authors: Di Finizio
authors: Gregory
authors: G
authors: Kozyreff
authors: Jordi
authors: J
authors: Martorell