We report the experimental observation of difference-frequency generation in gold nanoparticles under localized surface plasmon excitation. A zero-delay peak is detected in the differential transmission signal for a gold nanoparticle film with a MgF2 overlayer, showing that the energy transfer from pump light to probe light through the difference-frequency generation is resonantly enhanced by the excitation. This peak of differential transmission decreases in strength with higher probe fluences. Both the enhancement and the power dependence of the difference-frequency generation are explained by modeling the localized surface plasmons as a nonlinear Lorentz resonator.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)