Investigation of An Elliptic Terahertz Absorber Based On Vanadium Dioxide

In this research article, we show a tunable broad- band absorber based on a simple elliptic structure using vanadium dioxide at terahertz frequencies. We use a single elliptic resonator ring which is made of vanadium dioxide (VO
2
), positioned on top of a layer of metal and separated by a dielectric spacer. Through full vector numerical simulation, we calculate the absorption bandwidth in the given range, achieving nearly complete absorption (100%) throughout the span of frequencies from 3.5 THz to 4.7 THz. Our theoretical analysis reveals that modifying the ratio
$\eta$
of the semimajor and semiminor axis of the ellipse changes the absorption peak intensity and operating bandwidth as well. The proposed structure also experiences a change in the radii of the semimajor axis which eventually results in a change in the absorption rate. Because of the conductivity of VO
2
that controls the properties of the substance, also responsible for the enhancement of the intensity of absorption. Interestingly, we observe that varying the incident angle
$\theta$
, modifies the absorption magnitude within the asymmetric structure. The distinct reliance on the angle of incidence offers possibilities for applications in the progress of sensing and imaging technology.