Hyper-Rayleigh scattering from silver nanoparticles

We experimentally demonstrate for the first time the existence of distinguishable contributions to hyper-Rayleigh scattering (HRS) intensities from Ag nanoparticles arising from electric–dipole and electric–quadrupole plasmon resonances at the emitted wavelength. We show that these results can be successfully modeled using an electromagnetic theory of HRS which assumes a surface-induced nonlinear susceptibility. In addition, we show that simple angular distribution measurements may be used to determine the relative sizes of the dipole and quadrupole contributions.