Thz propagation in cut-through metal slit array metamaterials

Cut-through metal slit arrays behave like dielectrics, the refractive indices of which are determined by the ratio of the slit period and the slit width. We have investigated the propagation characteristics of THz waves in a double layer system of cut-through metal slit arrays and found that the system behaves like a three dielectric layer system, although the effective refractive index of the air gap layer depends strongly on the configuration.