Refractive index sensor based on terahertz metamaterial absorber

For refractive index sensing applications, a simple Terahertz (THz) Metamaterial Absorber (MMA) is proposed. Without using the multiple layers and multiple resonator processes, the numerical simulation results demonstrate that the absorber has six separate absorption peaks ranging from 0.74 THz to 0.95 THz. Electric and magnetic field distributions are used to examine the structure's physical mechanism. We describe the results of one THz MMA structure in this paper, focusing on two key device aspects: polarization (phi) and incident angle (theta) insensitivity, as well as sensing application at a fixed overlayer thickness, the proposed MMA resonant frequency is sensitive to the surrounding medium Refractive Index (RI). By adjusting the analyte RI value, the structure's performance parameters such as Q-factor, Figure of Merit (FOM), Sensitivity (S), and Full Width Half Maximum (FWHM) are explored using a numerical technique. Through a RI range of 1 to 1.41 at a fixed over-layer thickness of 1 mu m, the reported MM design provided a RI sensor with a high sensitivity of 940 GHz/RIU, a Qfactor of 323, and a FOM of 393. The RI values are based on the RI values of biological samples. As a result, the MMAbased sensor reported here can be employed for biological applications as well as fluidic sample detection with extremely high sensitivity. We compared the six absorption peaks FOM, Q-factor, and S-values in this work with previously published publications, as well as the resonant frequency ranges, sensing results, and number of bands.