Polarization manipulation of electromagnetic wave or polarization multiplexed beam shaping based on metasurfaces has been reported in various frequency bands. However, it is difficult to shape the beam with multi-channel polarization conversion in a single metasurface. Here, we propose a new method for terahertz wavefront shaping with multi-channel polarization conversion via all-silicon metasurface, which is based on the linear shape birefringence effect in spatially interleaved anisotropic meta-atoms. By superimposing the eigen- and non-eigen-polarization responses of the two kinds of meta-atoms, we demonstrate the possibility for high-efficiency evolution of several typical polarization states with two independent channels for linearly polarized waves. The measured polarization conversion efficiency is higher than 70% in the range of 0.9–1.3 THz, with a peak value of 89.2% at 1.1 THz. In addition, when more other polarization states are incident, combined with the integration of sub-arrays, we can get more channels for both polarization conversion and beam shaping. Simulated and experimental results verify the feasibility of this method. The proposed method provides a new idea for the design of terahertz multi-functional metadevices.

中文翻译：

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基于全介电超表面的多通道偏振转换太赫兹波前整形

电磁波的偏振操纵或基于超表面的偏振复用光束整形已在各种频段中有所报道。然而，很难在单个超表面中使用多通道偏振转换对光束进行整形。在这里，我们提出了一种通过全硅超表面进行多通道偏振转换的太赫兹波前整形新方法，该方法基于空间交错各向异性超原子中的线性形状双折射效应。通过叠加两种超原子的本征和非本征极化响应，我们证明了几种典型极化状态的高效演化的可能性，这些极化状态具有两个独立的线性极化波通道。测得的偏振转换效率在 0.9-1 范围内高于 70%。3 THz，在 1.1 THz 处峰值为 89.2%。此外，当更多的其他偏振态入射时，结合子阵列的集成，我们可以获得更多的偏振转换和光束整形通道。仿真和实验结果验证了该方法的可行性。该方法为太赫兹多功能元器件的设计提供了新思路。