应用于THz波的非对称双开口环传输特性研究

设计并制备了一种适用于太赫兹波段的非对称双开口环结构,数值仿真和实验测量了其传输性质.结果表明,垂直极化时样品在低频的0.540 THz和0.925 THz处存在谐振点,来源于左右两开口环的LC谐振,电流和电场分布主要集中在两开口环的开口处;而在高频处(1.885THz)谐振点的表面电流具有相反的两个环流方向,电流和电场分布于整个样品表面,此处的谐振来源于两开口环耦合后的偶极子谐振.当太赫兹波平行极化该样品时,原来两个低频的LC谐振消失.实验测量结果与数值仿真具有很好的一致性.此结构超材料的传输特性研究对太赫兹波调制器、滤波器、吸收器及偏振器等器件设计和制备具有一定的指导意义.

Transmission characteristic of asymmetric double-split ring resonator in terahertz wavelength

An asymmetric planar terahertz metamaterial (MM), composed of two different single split-ring resonator (SRR), was designed and fabricated. Its transmission performance was obtained through numerical simulation and experiment. The simulations revealed that, under the case of perpendicular polarization, two transmission dips occurred at the lower frequencies 0.540 THz and 0.925 THz, which were attributed to the inductor-capacitor (LC) resonances of the left and right rings respectively. At these two frequencies, the surface current and electric field mainly concentrated around the gaps of the two rings. At the higher frequency 1.885 THz, there was another transmission dip which originated from the dipole resonance of the sample. At this time, the surface current had two opposite circulation directions, and besides, the electric field and surface current were distributed throughout the sample. However, the two lower-frequency LC resonances would be absent when the polarization direction of incident terahertz waves was rotated 90. The experiment results coincide well with the numerical simulations. This metamaterial structure was expected to provide important reference for the design of terahertz modulator, filters, absorbers and polarizers.