Planar terahertz metamaterial with three-resonant frequencies

In this paper, we study a three-resonant metamaterial with the combination of dual-resonant and single-resonant metamaterials. It presents a new method to design multi-resonant metamaterial which has a smaller dimension than the general symmetric and asymmetric multi-resonant metamaterials. Theoretical and experimental results show that the structure has three distinct absorption frequencies centering around 0.29 THz, 0.46 THz, and 0.92 THz, and each of them corresponds to a different resonant mode. Due to the well-separation of different resonances, this design provides a unique and effective method to construct multiband terahertz devices.