基于曲折线型介质超材料的宽带太赫兹四分之一波片

发布时间：2018-06-04 03:01

本文选题：太赫兹 + 介质超材料　；参考：《红外与激光工程》2017年09期

【摘要】：采用基于高阻硅的曲折线型(meander-line)介质超材料,设计了一种宽带的太赫兹四分之一波片,可以在较宽的频率范围内将入射的线偏振太赫兹波转换为圆偏振太赫兹波出射。三维全波模拟显示,通过恰当地设计超材料微结构的几何尺寸,可以调节微结构的双折射特性,进而改变沿微结构两个正交方向偏振的太赫兹波的透射振幅和相位,使之振幅相近(约0.55),相位相差90°。实验上,通过离子束刻蚀硅的方法按照设计加工了一个样品,并利用太赫兹时域频谱系统进行了表征。实验结果和模拟结果吻合得很好,实现了带宽在1.07~1.41 THz范围内有效的四分之一波片,对应的归一化椭圆率高达0.99,证实了该设计的有效性。此外,还通过改变微结构的几何参数,进一步在模拟上设计了两个在其他太赫兹波段工作的四分之一波片,证明了该微结构的可调谐特性。
[Abstract]:A wideband terahertz 1/4 wave plate based on high resistivity silicon zigzag meander-line-based dielectric supermaterial is designed. The incident linear polarization terahertz wave can be converted into circularly polarized terahertz wave emission in a wide frequency range. Three-dimensional full-wave simulation shows that the birefringence of the microstructures can be adjusted by properly designing the geometric dimensions of the microstructures, and the transmission amplitude and phase of the terahertz waves polarized along the two orthogonal directions of the microstructures can be changed. The amplitude is similar (about 0.55) and the phase difference is 90 掳. A sample was fabricated by ion beam etching method and characterized by terahertz time-domain spectrum system. The experimental results are in good agreement with the simulation results. An effective 1/4 wave plate with a bandwidth of 1.41 THz is realized, and the normalized ellipse ratio is as high as 0.99, which proves the effectiveness of the design. In addition, by changing the geometric parameters of the microstructures, two 1/4 wave plates operating in other terahertz wavebands are designed and simulated. The tunable characteristics of the microstructures are proved.
【作者单位】：天津大学精密仪器与光电子工程学院光电信息技术科学教育部重点实验室天津大学太赫兹波研究中心;
【分类号】：O441.4

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