Multifunctional terahertz metamaterial based on vanadium dioxide and silicon

This paper proposes a multifunctional metamaterial device operating in the terahertz (THz) band. The metamaterial device can switch functions by using the phase transition properties of vanadium dioxide (VO 2 ) and the photoconductive effect of silicon. An intermediate metal layer divides the device into the I side and II side. When VO 2 is in the insulating state, the I side can achieve polarization conversion from linear polarization waves to linear polarization waves at 0.408–0.970 THz. When VO 2 is in the metal-like state, the I side can perform polarization conversion from linear polarization waves to circular polarization waves at 0.469–1.127 THz. When silicon is not excited in the absence of light, the II side can perform polarization conversion from linear polarization waves to linear polarization waves at 0.799–1.336 THz. As the light intensity increases, the II side can realize stable broadband absorption at 0.697–1.483 THz when silicon is in the conductive state. The device can be applied to wireless communications, electromagnetic stealth, THz modulation, THz sensing, and THz imaging. Moreover, it provides a fresh idea for the design of multifunctional metamaterial devices.