1：Experimental Design and Method Selection:

The study utilized 3D full-wave simulations with COMSOL Multiphysics to optimize the design of metal-insulator-metal unit cells for the metasurface. The methodology involved designing a quarter-wave plate and extending it to generate vector vortex beams by spatially varying the orientation of unit cells.

2：Sample Selection and Data Sources:

Samples were fabricated on silicon wafers with gold and silicon dioxide layers. The design was based on simulations at a wavelength of 850 nm, with performance evaluated across 750–950 nm.

3：List of Experimental Equipment and Materials:

Equipment included an electron-beam lithography system for fabrication, a scanning electron microscope for imaging, a tunable Ti:Sapphire laser for illumination, half-wave plates, linear polarizers, quarter-wave plates, beam splitters, objectives, lenses, mirrors, and a CCD camera for detection. Materials included gold, silicon dioxide, titanium, poly(methyl methacrylate), and silicon substrates.

4：Experimental Procedures and Operational Workflow:

Fabrication involved electron-beam lithography, thin-film deposition, and lift-off processes. Optical characterization used a homemade setup to measure reflectance and polarization states with incident circularly polarized light, analyzing reflected beams with a linear polarizer and CCD camera. Interference experiments were conducted to verify phase singularities in generated beams.

5：Data Analysis Methods:

Data analysis involved calculating degree of linear polarization and angle of linear polarization from measured intensities, using Stokes parameters. Efficiencies were computed as the ratio of power in the generated beam to incident power, with averages and errors reported.