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

Generation of arbitrary vector vortex beams on hybrid-order Poincaré sphere based on liquid crystal device

We propose theoretically and verify experimentally a method of using electrically tunable liquid crystal q-plate and wave plate for generating arbitrary vector vortex beams on a hybrid-order Poincaré sphere (HyOPS). The generated vector vortex beam is verified and shows decent agreement with the prediction. This method brings many advantages, such as high conversion efficiency, good electrical controllability, and integration. This system can provide fundamental optical system support for various structured beam applications.

Visible-broadband Localized Vector Vortex Beam Generator with a Multi-structure-composited Meta-surface

We demonstrate a vortex beam generator meta-surface that consists of silver structures and graphene layers. The miniature material is just a few microns in size and the working part is only a few hundred nanometers thick. With the incidence of the linearly polarized beam, the meta-surface generates high-localized vector vortex beam with a high proportion of the longitudinal component. Being compared with the constituent part of the meta-surface, the multi-structure-combined meta-surface increases the localization by 250% and the longitudinal component proportion by 200%. Moreover, the above artificial material can generate vortex beams in broadband within the visible light range. These novel optical properties have the potential to improve the precision and sensitivity of nanoparticle manipulation. The study serves as a foundation in optical miniaturization and integration, nanoparticle manipulation, high-efficiency optical and quantum communication, and light-driven micro-tools.

Dielectric metasurfaces enabling twisted light generation/detection/(de)multiplexing for data information transfer

We propose, design, fabricate and demonstrate nanophotonic all-dielectric metasurfaces enabling the generation, detection and (de)multiplexing of twisted light having helical phase structure and carrying orbital angular momentum (OAM). The designed metasurfaces are based on dielectric elliptical resonators on standard silicon-on-insulator (SOI) platform. One can achieve full-phase control of 0-2π and flexible amplitude adjustment by properly changing the geometric dimensions (long axis, short axis) and orientation of dielectric elliptical resonator based on the Mie resonance effect. Using the designed and fabricated all-dielectric metasurfaces, we demonstrate the generation and detection of OAM beams with topological charge number from l = -4 to 4. The crosstalk matrix of generated OAM beams is also characterized showing -16 dB crosstalk. We further demonstrate the (de)multiplexing of two OAM beams (OAM₊₁ & OAM₊₄ or OAM₊₂ & OAM₊₃) each carrying a binary image ("A" & "B" or "HUST" & "WNLO"). The obtained results show error-free data information transfer with favorable performance. The presented alternative approach of all-dielectric metasurfaces shows distinct features of easy fabrication process and easy chip-scale integration facilitating ultrathin optical applications. The demonstrations may open a door to find more interesting applications in all-dielectric metasurfaces enabled spatial light manipulation and optical communications and interconnects.