Terahertz beam reconfigurable phase gradient metasurface of VO2 based on different metal–insulator transition temperatures

Abstract

In this letter, by using vanadium dioxide (VO₂) with metal–insulator transition (MIT) temperatures of 60 ℃ and 72 ℃, respectively, and analyzing the effects of the two states of VO₂ before (insulator state) and after (metal state) MIT on the amplitude and phase of the double MIT VO₂ (DMITV) unit structure, constituting the terahertz beam reconfigurable phase gradient metasurface of VO₂ based on different MIT temperatures, which achieves flexible regulation of terahertz beam. The structure is composed of two different MIT temperature VO₂, polytetrafluoroethylene (PTFE) and metal. By changing the external temperature, the structure has different beam deflection angles at different temperatures. At 1.4 THz, when the temperature is below 60 ℃, the beam deflection angle is 0°, when the temperature is between 60 ℃ and 72 ℃, the beam deflection angle is 36° and when the temperature is above 72 ℃, the beam deflection angle is 17°. This terahertz phase gradient metasurface based on VO₂ with different MIT temperatures provides a new way to flexibly control terahertz beams, and will have great application prospects in terahertz transmission, imaging, wireless communication, or other fields.