Terahertz broadband tunable multifunctional metasurface based on VO2

A switchable multi-function terahertz metasurface employing phase transition material vanadium dioxide (VO 2 ) is presented and investigated. By varying the temperature, the hybrid structure can switch between transmission, absorption, and reflection modes in broadband ranges. When the temperature is below 340 K and VO 2 is in the insulating state, perfect polarization conversion is demonstrated. Efficient asymmetric transmission (AT) exceeding 0.7 is simultaneously achieved with an ultra-wide bandwidth of 3.6THz. When VO 2 is in the metal phase, it shows different modulation characteristics for x and y-polarized waves. The structure can absorb over 90% of y-polarized waves from 3.56 THz to 7.2 THz (bandwidth, 3.64 THz), while 85% of x-polarized waves are reflected from 1 THz to 9 THz (bandwidth, 8 THz). Compared with other related published works, the designed structure makes significant progress in integrated functionalities, operating bandwidth, and working efficiency. It shows great potential for use in terahertz dynamic control and multifunctional integrated systems.