In light of the powerful light manipulation ability of holographic metasurfaces, optical imaging with wavelength multiplexing and polarization multiplexing is performed in this paper. The metasurface is composed of identical rectangular nanoholes etched in silver film. Three imaging effects, including the in-plane color imaging, three-dimensional wavelength-encrypted imaging, and polarization-multiplexing wavelength-encrypted imaging, are realized. The designed metasurface has compact structure, and the obtained image has lower noise. The simulation and experiment results give the verification. Multiple images, including spatial multiplexing, wavelength multiplexing, and polarization multiplexing, exhibit immense potentialities of metasurfaces, and this work is helpful for expanding the applications of metasurfaces.

Highly customized and miniaturized structured light is expected in many application fields. A kind of structured vortex generators is proposed based on a metasurface consisting of rectangular nanoholes etched in a silver film, and the generated vortices with the same or different topological charges are distributed along the radial direction. The geometric metasurface is completed with the help of optical holography technology, and the structured vortex generator possesses high working efficiency and large information capacity. The proposed vortex generators work under circularly polarized light illumination, and the reproduced vortices of multiplexing vortex generator depend on the handedness of the circularly polarized light. This work paves a way to generate new structured light fields. The radially distributed vortices may be utilized to simultaneously screen or separate microparticles. The compact design of the structured vortex generator and the convenient switch of different structured vortices will be a benefit to expand the applications of structured vortex fields.

Transmission of an anisotropic metasurface is analyzed in a polar base relying on the Jones calculus, and polarization conversion from the spatial uniform polarization to the spatial nonuniform polarization is explored. Simple and compact polarization converters based on rectangular holes or cross holes etched in silver film are designed, and polarization conversions from the linear and circular polarization to the radial and azimuthal polarization are realized. Numerical simulations of three designed polarization converters consisting of rectangular holes equivalent to polarizers and quarter- and half-wave plates, exhibit the perfect polarization conversion. The experiment results consistent with the simulations verify theoretic predictions. This study is helpful for designing metasurface polarization converters and expanding the application of a metasurface in polarization manipulations.