宽带太赫兹超表面带通滤波器

Broad Bandpass Terahertz Metamaterial Filter

提出一款宽带太赫兹超表面带通滤波器,测试得到滤波器中心频率为0.344 THz,3 dB带宽为56.6%。在对样品进行太赫兹时域光谱测试时,发现氮气的引入能够有效降低空气中水吸收引起的损耗。与以前报道的金属-介质-金属结构的带通滤波器采用电磁场或表面电流和电路模型进行物理机理描述不同,采用两种理论模型对带通滤波器分别进行了宽带传输的物理机理研究。一种是多重散射理论,一种是耦合模理论,这两种理论模型的拟合与实验测试和仿真结果一致,从而为太赫兹、微波和光波段的多层宽带超表面带通滤波器的设计提供了重要的理论指导。

An ultrabroad bandpass terahertz metamaterial filter is demonstrated with the 3 dB relative bandwidth 56.6%at the center frequency of 0.344 THz.Based on the terahertz time-domain-spectroscopy technique,we find the insertion loss of the passband decreases greatly as Nitrogen is filled to reduce the water absorption of the THz wave.Different from the terahertz metal-dielectric-metal(MDM)sandwich metamaterial filters reported before,both the multiple interference model and the coupled-mode theory are introduced to discuss the physical mechanism of the broadband transmission.The two theoretical calculations are in good agreement with the experiment and simulations.This research would provide new theoretical instructions for analyzing multilayer metamaterial filters in the terahertz,microwave or the optical bands.