Terahertz Plasmon-Induced Transparency Effect in Parallel Plate Waveguide

Recently reported metamaterial analogues of plasmon-induced transparency are very promising in designing novel optical components, such as slow-light devices and optical switches. However, most of the previous works mainly focus on manipulating the PIT effects using planar structures in the free space under normal incidence, where the resonances are mostly induced by the incident electric fields. Here, we present a PIT analogue in a waveguide system in the terahertz regime by inserting coupled split-ring resonator pairs into a tapered parallel plate waveguide. Different from the free-space cases, the incident magnetic fields can also play an important role here. By carefully arranging the relative orientations of the coupled split-ring resonators in each pair, giant modulation of the PIT effect is observed. This straightforward approach may enable novel devices for integrated terahertz devices.