Optically and thermally controlled terahertz metamaterials using semiconductor plasmon

We present a novel design of tunable terahertz metamaterials. The design numerically shows that the amplitude transmission reaches 86.4%, the intensity modulation depth reaches 96.4%, the response time reaches 1360 ps, and the bandwidth exceeds760 GHz. The metamaterial consists of a semiconductor layer and a metal layer separated by air. Under optical excitation condition, the electromagnetic properties of the semiconductor change from semi-insulating to metallic and then the amplitude transmission is mainly affected by Fabry-Perot interference and spoof surface plasmon polaritons (spoof SPPs). Furthermore, we analyze the relationship between the amplitude transmission peak determined by spoof SPPs and the design geometries using the mode expansion method. A tunable terahertz metamaterial, as a functional device, is a basic element in terahertz high-volume, wireless communication systems, which are of vital importance.