Highly sensitive quad-ray shaped polarization insensitive THz meta-biosensor

Metasurface-based sensors are now becoming crucial for label-free and rapid-detection technologies in biomedical applications, leading to a growing demand for new highly sensitive meta-biosensors. This paper demonstrates a perfectly symmetrical quad-ray X-shaped THz meta-absorber (QRXMA), enabling narrowband and polarization insensitivity performance. The theoretical modelling and performance investigation focuses on its potential for improved refractive index (RI) sensing for multiple biological samples. The simulation outcomes reveal that the proposed optimal QRXMA achieves an absorption rate of 99.98% at 1.3 THz for both TE and TM polarized incidences. Furthermore, we highlight the adjustability of absorptive characteristics of the proposed device by altering the different geometric parameters. These findings underscore the QRXMA potential in RI sensing applications, achieving a sensitivity of approximately 116.8 GHz RIU −1 and a figure of Merit (FoM) of about 2 with an 8 μm thick non-destructive analyte layer. This research makes a significant contribution to the development of highly efficient meta-biosensors with promising applications in THz detection, sensing, and imaging.