MXene-Based Perfect Absorber Design and Refractive Index Sensing Performance

In this study, a MXene-based electromagnetic absorber with a simple design at terahertz frequencies is proposed. An absorber that has a MXene layer drilled into with square and circular cavities and a thin aluminum layer as a reflector was examined. With the proper design of the structure dimensions, a MXene-based refractive index sensor with a dual-band at THz frequency and 99.93%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$99.93\%$$\end{document} and 97.85%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$97.85\%$$\end{document} absorption levels were obtained. The proposed design achieved 1983 and 1935 Q-factor values at frequencies of 0.446 THz and 0.583 THz, respectively. The proposed sensor with fractional bandwidth of 0.050%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.050\%$$\end{document} and 0.052%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.052\%$$\end{document} has sensitivity values of 686.2 and 557.6 (GHz/RIU). The figure of merit of the proposed sensor is calculated as 3049.8 and 1852.5 (1/RIU), and the proposed sensor is compared with sensor available in the literature. Since the designed absorber can detect refractive index changes, it also has potential applications in the identification of biological samples.