Design and Analysis of a Vanadium Dioxide-Based Terahertz Absorber
Mohammad Abrar Nasif, Abdullah Al Hossain Newaz, Nowshad Hasan, Md. Rafiul Haq, Md Mahatab Uddin, Md. Nazim Uddin Niloy
Abstract
In this research article, we present a versatile broadband absorber employing vanadium dioxide, designed for effective absorption at terahertz frequencies. The absorber is comprised of two squares outside split rings and two elliptical resonance rings placed at a 90 -degree angle to each other at the center, utilizing vanadium dioxide $\left(\mathrm{VO}_{2}\right.$). By conducting comprehensive numerical simulations, we determine the absorption bandwidth within the specified range. Our calculations demonstrate absorption levels exceeding 90 % across frequencies ranging from 2.70 THz to 5.53 THz. Moreover, the intensity of the absorption peak can be actively adjusted, spanning from 1.8 % to 99.9 %, through continuous modulation of the conductivity of VO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> within the range of $2 \times 10^{2}$ $\mathrm{S} / \mathrm{m}$ to $2 \times 10^{5} \mathrm{S} / \mathrm{m}$. Notably, we observe that altering the incident angle $\theta$ leads to changes in the absorption magnitude within the asymmetric structure. The findings outlined in this research have the potential for practical applications in adjustable spectral capabilities for devices functioning within the terahertz frequency range. This includes applications in sensors, detectors, and thermophotovoltaic devices.