Complementary Plasmonic Arrays for Extraordinary Transmission and Modulation of Terahertz Wave

An extraordinary optical transmission effect in a complementary metallic disk and hole array has been experimentally and numerically investigated in the terahertz (THz) regime, which shows a high transmission peak despite having zero effective aperture in the direction of light propagation. The results confirm that this effect is contributed not only by the surface plasmon excited on metallic disk and hole but also the resonance in the dielectric rod between them. Moreover, an optically pumped THz wave modulation with 40% amplitude modulation depth has been demonstrated in this device using a 532-nm laser with only 150 mW/mm² power density. This novel plasmonic structure with high Q transmission peak shows great promising applications in the THz modulation, filtering, and sensing.