Generation of cylindrical vector vortex beams for self-assembly of chiral nanostructures of AuNPs

The radially polarized vortex beams with excellent focusing characteristics, provide a useful tool for the self-assembly of chiral nanostructures of nanoparticles. Here we presented a simple method for producing cylindrical vector vortex beams. This technique involves converting linearly polarized scalar vortex beams into cylindrically polarized vector vortex beams without the need for strict dual-optical path alignment. The phase hologram loaded onto the spatial light modulators is newly designed to generate linearly polarized vortex beams with different topological charges, concentrating the energy mainly on the first-order diffractions and significantly increasing the energy utilization. Then, the generated beams are introduced to vector polarization using a q-plate to produce radial or azimuthal vector vortex beams. We prepared an AuNPs growth solution comprising CTAB (50 mM, 21.08 mL), HAuCl4 (20 mM, 140 μL), and AA (100 mM, 0.653 mL). SEM images and circular dichroism spectra of the AuNPs exhibit strong chiral nanostructures (L/D-PX AuNPs). We believe that the cylindrical vector vortex beams generated by this method can provide a useful tool for the self-assembly of chiral nanostructures, super-resolution microscopy, optical trapping, and more.