基于开口圆环结构的太赫兹分束器设计

Design of Terahertz Beam Splitter Based on Open Ring Structure

提出了一种基于开口圆环结构的太赫兹分束器,其由两种单元结构组成,这两种结构的区别在于是否存在底层连续金属层,这两种结构的顶层金属图案由开口圆环组成,介质层为聚酰亚胺薄膜。通过改变开口圆环的开口大小和半径排列构成了8×8的相位梯度超表面。当太赫兹波分别沿-z轴方向和+z轴方向垂直入射时,电磁波会被分成沿x,y轴对称但能量分布不同的四束波,两种入射模式能够得到两种不同的分束比。在0.7 THz下,当太赫兹波分别沿-z轴方向和+z轴方向垂直入射时,其分束比分别为0.8∶1和1.9∶1,实现对分束比的调谐。此分束器具有体积小、成本低的优点,可应用于太赫兹通信、太赫兹成像和太赫兹隐身等领域。

In this paper,a terahertz beam splitter based on an open ring structure is proposed.Its structural unit is a typical metal-dielectric-metal structure.The top metal pattern has the form of an open ring,and the bottom layer is a continuous metal plate.An 8×8 phase gradient metasurface is formed by changing the opening size and radius of the opening ring.When the terahertz wave is vertically incident along the-z and +z axes,the electromagnetic wave will be divided into four beams that are symmetrical along the x and y axes but have different energy distributions.The two incident modes can obtain two different beam splits.At 0.7 THz,when the terahertz wave is vertically incident along the-z and +z axis directions,the beam splitting ratios are 0.8∶1 and 1.9∶1,respectively,realizing the tuning of the beam splitting ratio.This beam splitter has the advantages of small size and low cost,and it can be applied in the fields of terahertz communication,terahertz imaging,and terahertz stealth.