Despite the growing interests for controlling terahertz (THz) scatterings via metallic metasurfaces, the avoidance of Ohmic loss resulting from the interaction between light and phonons or free electrons remains an arduous task. Herein, we propose a new approach of ultra-wideband low-loss control of THz scatterings via an all-dielectric coding metasurface (DCMF). In our experiments, the DCMFs manipulate THz waves remarkably in an ultra-wideband of 900 GHz. When a THz wave enters into the DCMFs, it emerges split into two beams with a higher amplitude of transmission up to 60% and the lower amplitude about 30%. In our simulations, the high amplitude of transmission may even reach 99%. Besides, the variation of coding sequence enables diversification of manipulation for THz scatterings. Notably, the DCMF with the sequence of “101010...” refracts a beam of 1.3 THz in two directions. The energy of the main beam seems to dissipate in all directions. We also find that as a beam of 1.63 THz passes through the DCMFs consisting of the sequence of “110110...”, its energy may scatter in multiple directions, demonstrating an unprecedented control of THz scatterings. Our results not only enrich the strategy of THz modulation but also guide the superior design for THz devices.

中文翻译：

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通过全介电编码超表面对太赫兹散射的超宽带低损耗控制

尽管人们越来越关注通过金属超表面控制太赫兹（THz）散射，但是要避免因光与声子或自由电子之间的相互作用而导致的欧姆损耗仍然是一项艰巨的任务。在本文中，我们提出了一种通过全介电编码超表面（DCMF）控制THz散射的超宽带低损耗新方法。在我们的实验中，DCMF在900 GHz的超宽带中显着地操纵了太赫兹波。当太赫兹波进入DCMF时，它分成两束出现，其透射幅度最高可达60％，而较低的幅度约为30％。在我们的仿真中，传输的高幅度甚至可能达到99％。此外，编码序列的变化使THz散射的操作多样化。值得注意的是，DCMF的顺序为“ 101010 ... 在两个方向上折射1.3 THz的光束。主光束的能量似乎在所有方向上都消散了。我们还发现，当1.63 THz的光束通过由“ 110110 ...”序列组成的DCMF时，其能量可能会在多个方向上散射，这证明了对THz散射的空前控制。我们的结果不仅丰富了THz调制的策略，而且指导了THz器件的卓越设计。