Coherent stokes scattering from gold nanorods: Critical dimensions and multicolor near-resonant plasmon excitation

In this study, we detail the coherent Stokes scattering from gold nanorods in ensemble and single particle measurements. An increase of more than an order of magnitude was observed in the surface plasmon resonance enhancement of coherent Stokes scattering by gold nanorods for small changes in nanorod dimensions. The impact of this dimensional change is, in general, smaller when probed by single color linear and non-linear techniques. We find that the size sensitivity and associated wavelength dependence of the enhanced coherent Stokes scattering from individual gold nanorods is consistent with predictions based on local surface plasmon resonances found from exact solutions obtained using boundary element methods.