Abstract

Nonlinear optical effects in plasmonic metal nanostructures are attracting widespread interest [1]. The plasmonic resonances of individual nanoparticles can be modified by constructing oligomers of several particles, allowing the collective (simultaneous) excitation of several particles or the modification of the resonances of the overall structure by the interaction between the individual particles [2,3]. The collective effects can be accessed through near- or far-field methods by modifying the oligomeric configuration and by using illumination schemes that depart from traditional excitation geometries based, e.g., plane waves. Recently, linear optical response of oligomers has been tailored using beams that exhibit inhomogeneous polarization states, such as cylindrical vector beams (e.g., azimuthal and radial) [4,5]. Here, we design plasmonic oligomers whose structure is matched to the distribution of local polarization of tightly-focused cylindrical vector beams and demonstrate their potential in tailoring second-harmonic generation (SHG) on the nanoscale.

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