Anisotropic and nonlinear metasurface for multiple functions

We present a novel anisotropic and nonlinear metasurface integrated with multiple functions of diffuse scattering, beam splitting, and normal reflection, which can be switched in real time by tuning the polarization state or power level of the incident microwave. The key lies in the two judiciously designed anisotropic nonlinear particles in subwavelength scales that possess opposite reflection phases under one polarization and the same nonlinear power-dependent reflection phases under the orthogonal polarization. These properties are demonstrated comprehensively via comparisons between their reflection responses, receiving abilities, and nonlinear circuitry behaviors. In addition, both the spatial arrangement and the electrically enabling strategy of the particles are underpinned to pursue the proposed functions, which are verified through numerical simulations and measurements. When the metasurface is illuminated by plane waves coming from the direction perpendicular to it, a significant beam splitting effect is achieved with strong x-polarized incidence, which is switched to a specular reflection when the incoming power decreases. Under y-polarization, a diffuse scattering phenomenon is obtained, which is not dependent on the incident intensity. The study is expected to offer new solutions to many electromagnetic scenarios involving energy transmissions and protections.