Analyzing and Optimizing the Geometric Design of VO₂ Based Metamaterial Unit Cells for Enhanced THz Absorption Bandwidth

A dielectric separator separates the three vanadium dioxide (VO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) multiple-slit square ring resonators from the copper ground plane, enabling the construction of a dynamically tunable ultra-wideband terahertz (THz) ideal absorber. Slit length, VO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thickness, and resonator width were all system-atically optimized, and the result was an absorber with over 90% average absorptance over a remarkably large frequency bandwidth of 3.25 THz under normal incidence. Additionally, a consistent 95% absorption efficiency is achieved across a 2.65 THz bandwidth, demonstrating exceptional wide-angle absorption and polarization insensitivity. Beyond earlier THz absorber demonstrations, the VO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> 's dynamic tunability enables continuous adjustment of the absorption intensity from 4% up to 100% by altering its conductivity. Applications for such an efficient dynamically controlled broadband absorber are diverse and include THz modulators, switches, sensors, and other optical devices. The suggested geometric tuning techniques can aid in the development of flexible ultra-wideband VO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> metamaterial absorbers for upcoming broadband terahertz technology.