A metamaterial terahertz device with temperature regulation function that can achieve perfect absorption and complete reflection conversion of ultra wideband

Terahertz devices are an important field in terahertz technology. However, most devices currently have limited functionality and poor performance. In order to improve device performance and achieve multifunctionality, we have designed a terahertz device based on a combination of vanadium dioxide and metamaterials. By utilizing the phase transition characteristics of vanadium dioxide, the device has tunability. The device is made up of a triple-layer structure inclusive of VO2, SiO2, and Au. This device exhibits various advantageous features, including broadband band coverage, high absorption capability, dynamic tunability, a simple structural design, polarization insensitivity, and incident angle insensitivity. The simulation results show that by controlling the temperature, the terahertz device achieves a thermal modulation range of spectral absorptivity from 0 to 0.99. At a temperature of 313 K, the device exhibits complete reflection of terahertz waves. As the temperature increases, the absorption rate increases. When the temperature reaches 353 K, the device absorption rate reaches over 97.7% in the range of 5-8.55 THz. This study employs the effective medium theory to elucidate the correlation between conductivity and temperature during the phase transition of VO2. Simultaneously, the variation in device performance is further elucidated by analyzing and depicting the intensity distribution of the electric field on the device surface at different temperatures. Furthermore, the impact of various structural parameters on device performance is examined, offering valuable insights and suggestions for selecting suitable parameter values in real-world applications. These characteristic renders the device highly promising for applications in stealth technology, energy harvesting, modulation, and other related fields, thus showcasing significant potential.