Broadband terahertz absorber based on patterned slotted vanadium dioxide

Abstract

This study aims to explore broadband terahertz absorbers based on metamaterials by introducing a design featuring patterned slotted vanadium dioxide. This absorber structure includes a vanadium dioxide resonator layer, an intermediate Topas dielectric layer, and an underlying metal reflector layer. To enhance the absorption bandwidth, the vanadium dioxide resonant layer is strategically patterned to optimize impedance matching. Simulation outcomes reveal that, under positive incidence, the absorption rate exceeds 90 % within the frequency range of 1.5–4.2 THz. The absorber demonstrates a substantial absorption bandwidth of 2.7 THz, centered at 2.85 THz, corresponding to a relative bandwidth of 94.7 %. Additionally, through modulation of the conductivity of vanadium dioxide, the absorption peak can be finely tuned, spanning from approximately 2.5 %–99 %. In addition, it's angularly symmetrical and exhibits absorption properties for wide-angle incidence. The tunable terahertz absorber designed in this paper simultaneously achieves high absorption over a wide frequency range, is dynamically tunable, and has a simple structure. From the application point of view, it can provide a way to realize detection, and imaging in the terahertz range.