The optical properties of anisotropic material systems depend on the polarization of light. In order to fully utilize this for arbitrarily oriented individual nano-objects, such as anisotropic molecules, nanowires, or metal nanoparticles, it is necessary to be able to control the three-dimensional (3D) vectorial fields under strong focusing. This will allow the coupling of incident light to the nano-object to be controlled, opening new perspectives in, e.g., the characterization of molecular orientations and tunable nonlinear effects. The 3D focal fields depend on proper balance between the transverse and longitudinal field components, which depend on the polarization distribution of the incident beam before focusing. In the context of nonlinear effects, such opportunities have been demonstrated for radially and azimuthally polarized incident beams  and Hermite Gaussian HG10 beams . Here, we take a significant step further by experimentally demonstrating that spatially phase-shaped incident beams can drive second-harmonic generation (SHG) from a single nanostructure in a controlled way.
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