Switchable band-pass filter for terahertz waves using VO₂-based metamaterial integrated with silicon substrate

Terahertz (THz) waves are a promising candidate for detection, imaging, and advanced communications with ultrafast transmission speed. To develop THz technologies, miniaturized devices for controlling THz waves are essential. In this study, a high-performance vanadium dioxide (VO₂)-based switchable band-pass metamaterial integrated with a silicon substrate for THz waves is designed and fabricated. In the “on” state, it offers a passband with a 70% depth and a 0.34 THz bandwidth at 0.56 THz frequency. Additionally, it can be switched thermally to a mirror for 0.1–2.0 THz waves in the “off” state by the phase transition effect of the VO₂ film. Moreover, the relationship between the line width and spectra of the device is investigated by simulation. The wheel-shaped gold structure with round corners provides the filter with tractability during fabrication. Furthermore, the silicon substrate allows the metamaterial to be readily miniaturized and integrated into micro-electromechanical systems (MEMS) technology. This filter is expected to be favorable in frequency-selective THz applications.