We theoretically demonstrate high efficiency broadband vector beams generation with polarization rotation metasurfaces composed of L-shaped silver antenna array, silica spacer, and silver ground plane. 0° to 90° arbitrary optical rotation with high degree of linear polarization (DoLP) over a broadband can be achieved readily by adjusting arm length of the L-shaped antenna. And through turning the L-shaped antennas upside down, the 0° to 90° optical rotation can be turned into 0° to -90°. Reflected phase can be shift by π after a 90° rotation of the L-shaped or Γ-shaped antennas, while optical rotation angle remains the same. Then six discrete units are designed to realize 0° to 360° polarization rotation with a step of 60°. With the combination of these units, we proposed metamaterial structures for highly efficient generation of radially polarized and azimuthally polarized vector beams.
We present a quarter-wave plate composed of two pairs of cross-shaped elliptical nanoatennas. This setup can transform linearly polarized incident light to circular polarized light at a wavelength of 862nm. The cross-shaped elliptical configuration can control the amplitude and phase of incident light. By the modulation of the elliptical size, equal amplitude and specific phase difference can be obtained in orthogonal directions. Furthermore, as a quarter-wave plate, this configuration is not sensitive to the polarized direction of the linearly polarized incident beam. In order to verify the designed metasurface, numerical simulation were performed using the finite difference time domain method. Our results may benefit novel photonics devices design such as polarization manipulation, optical sensing, optical detecting, and photonic integration.