Tunable terahertz metamaterial for high-efficiency switch application

We present two types of tunable terahertz (THz) metamaterials (TTM-1 and TTM-2) to explore their extraordinary optical properties. The proposed TTMs are composed of Au layers with 300 nm in thickness on Si substrates. The designs of TTMs exhibit superior properties in adjustability for high-efficiency THz switching characteristic. By changing the geometrical dimensions of TTMs, the corresponding electromagnetic responses could be tuned and switched between single-band and dual-band resonances. TTM-1 exhibits three switching windows with higher switching ratios by embedding different materials into the cavity underneath the complementary metamaterial. TTM-2 can be tuned to have two resonances and then merge into one resonance by increasing the height between the inner and outer rings. The transmission intensity of TTM-2 can be tuned from 0 to 0.7 at 0.57 THz by changing the sizes of inner and outer rings. TTM-2 exhibits tunable filter, single-/dual-band switch, tunable free spectrum range, and tunable bandwidth characteristics by varying the radius of the inner and outer rings. This study paves a way to the possibility of tunable high-efficiency switch, filter, polarizer, and other THz applications.