Temperature-mechanically reconfigurable bidirectional multifunctional metasurface

Abstract

In this paper, we propose a temperature-mechanically reconfigurable bidirectional multifunctional metasurface based on vanadium dioxide, which can operate in both forward and backward working modes and function as a reflective absorber in terahertz frequency range, as well as a reflective and transmissive polarization converter. In the forward mode, by mechanically rotating the top polarization modulation layer at the temperature of over 340 K, the metasurface can switch between reflective linear polarization (LP) converter and absorber. When the metasurface works as a reflective LP converter, the polarization conversion rate exceeds 90 % in 0.75–1.15 THz. Also, the LP wave can be converted to the right-handed circularly polarized (RHCP) wave at 0.56 THz; when the metasurface is utilized as an absorber, the absorptivity is above 90 % in 1.14–1.21 THz and reaches a peak of 95.6 % at 1.18 THz. In the backward mode, the metasurface can act as a transmissive polarization converter and an absorber at the room temperature. When the metasurface as a transmissive polarization converter, the LP wave is converted to the RHCP wave at 1.0 THz; when it works as an absorber, the absorptivity is over 90 % in 1.20–1.61 THz. Through temperature regulation and mechanical reconfiguration, the metasurface can achieve bidirectional multifunction including absorption, linear and circular polarization conversion, which is expected to be applied in antennas, electromagnetic stealth, military radar, terahertz communication, detection and other scenarios.