Vanadium Dioxide (VO₂) Based Wideband Tunable Terahertz Metamaterial Polarization-Insensitive Absorber

In this presented research paper, the proposed design of a wideband tunable terahertz (THz) absorber using the phase-changing material VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. The absorber has a wide bandwidth of 76.2% from 3.70 to 8.25 THz with an absorption level of more than 95%. For oblique incidents, the THz wave has an absorption level of more than 65% up to 60° incident angles. Due to the presence of the symmetry of the structure, it exhibits polarization-insensitive characteristics for both TE and TM THz-wave. Moreover, by changing the phase of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> from insulator to conductor 200 to 2×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> S/m with temperature, the absorption level can be varied from 2% to 98% under the wideband. The proposed absorber could be useful in absorber devices for terahertz technology in fields such as energy harvesting, imaging and security.