Plasmonic nanoparticle assemblies have great potential as functional units in light-harvesting devices. The inherent structural heterogeneity of colloidal metal nanoparticles renders predictive descriptions of the nanoparticle light-matter interaction difficult to achieve. Here, we describe nonlinear optical (NLO) imaging methods capable of quantifying both the electric and magnetic responses of single plasmonic nanostructures, thus overcoming these limitations. Our NLO method is based on analyzing the second harmonic generation signal amplitude from single metal nanostructures as a function of the polarization state of the incident fundamental wave. The accuracy of this NLO imaging method is demonstrated using a comparison of results obtained from lithographically prepared samples of chiral and achiral point group symmetries. We show that plasmon amplification of magnetic dipolar transitions can be exploited to increase circular dichroism image contrast. In this way, plasmonic nanoparticles can be used as both electric and magnetic field transducers, which may lead to the development of spatially resolved and single-molecule magneto-optical imaging.

Probing magneto-plasmonic phenomena at the single nanostructure level

249th National Meeting (2015)

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