Plasmonic Fishnet Structures for Dual Band THz Left-Handed Metamaterials

Plasmonic fishnet structures are proposed to realize dual-band terahertz (THz) left-handed metamaterials (LHMs). The calculated permittivity epsilon and permeability mu of single-layer LHMs show that epsilon < 0 and mu < 0 can be simultaneously satisfied in two frequency bands, resulting in dual-band LHMs. The electric and magnetic field distributions are consistent with the current distributions and confirm the physical mechanism of negative permeability. Furthermore, the existence of negative refraction is validated by a stacked LHMs prism with an angle of 1.79 degrees. It is shown that at 2.04-2.42 THz and 3.12-3.28 THz bands, negative refractive indices of the prism can be obtained, facilitating the practical application of LHMs in THz image, sensor, detection, communication, and so on.