Active Terahertz Spoof Surface Plasmon Polariton Switch Comprising the Perfect Conductor Metamaterial

The feasibility of realizing an active terahertz (THz) switch by utilizing artificially corrugated perfect conductor metamaterials is reported in this paper by demonstrating that the strongly localized THz spoof surface plasmon polariton (SSPP) modes can be easily controlled by changing the refractive index of dielectrics inside a longitudinal metallic structure with a periodic array of grooves. Specifically, this paper shows that incorporation of electrooptical material such as a nematic liquid crystal into the plasmonic gap leads to a highly compact and efficient THz switch that is activated by a low-voltage control-signal. The optimal design of the SSPP switch enabled by this novel method shows: 1) a strong subwavelength SSPP localization; 2) relatively high extinction ratio; and 3) small damping attenuation. Furthermore, the design flexibility associated with simple micrometer-scale architecture provides a promising method toward controlling or steering the subwavelength THz signal in the future SSPP-based compact digital circuit.