Vector vortex beam generation with dolphin-shaped cell meta-surface.

We present a dolphin-shaped cell meta-surface, which is a combination of dolphin-shaped metallic cells and dielectric substrate, for vector vortex beam generation with the illumination of linearly polarized light. Surface plasmon polaritons are excited at the boundary of the metallic cells, then guided by the metallic structures, and finally squeezed to the tips to form highly localized strong electromagnetic fields, which generate the intensity of vector vortex beams at z component. Synchronously, the abrupt phase change produced by the meta-surface is utilized to explain the vortex phase generated by elements. The new kind of structure can be utilized for communication, bioscience, and materiality.

Tuning of nanofocused vector vortex beam of metallic granary-shaped nanotip with spin-dependent dielectric helical cone.

We present the combined configuration of dielectric helical cone and metallic granary-shaped nanotip to produce three -dimensional vector vortex nanofocused optical field. The intensity and phase of the electric fields, and Povnting vector of the optical field generated by the combined configuration with linearly polarized illumination are studied with three-dimensional finite difference time-domain method. The localized vector electric field near the apex of the metallic granary-shaped nanotip is strongly depended on the chirality of the dielectric helical cone and the bottom radius of the metallic granary-shaped nanotip. The localized vector electric field is wavelength selective with the maximum intensity enhancement up to 104 times and minimum size of about 900 nm2, and the maximum radial electric field rotates 67.0° along z axis. This indicates the vector vortex beam generated by the combined configuration can be applied in nanofabrication, nano-sensing and nano-manipulation.