A Novel Ultra-Miniaturized Highly Sensitive Refractive Index-Based Terahertz Biosensor

This study describes the design and characterization of a highly sensitive THz refractive index-based metamaterial sensor for the detection of biological samples. The proposed ultra-miniaturized THz sensor is constructed using a fan-shaped resonator enclosed within a square loop. The proposed sensor has a footprint of 0.353 lambda(eff) x 0.353 lambda(eff) where lambda(eff) is the wavelength calculated at the operating frequency of 4.87 THz. The sensitivity of the THz sensor is estimated using the absorption characteristics of the metamaterial. The estimated free space absorptivity is 99.9%. The proposed sensor is polarization insensitive due to the rotational symmetry and it is angularly stable up to 60 degrees. The performance of the sensor is evaluated for different materials and biomedical samples. The results indicate that the proposed sensor has an average sensitivity of 1936 GHz/Refractive Index Unit (RIU). Furthermore, the influence of the sample thickness is analysed, and the results are presented. From the results, it is inferred that the proposed THz sensor has a good Figure of Merit (FoM) and is suitable for chemical sensing, including the nucleic acids and other components present in the biological samples.

Automated summary

This study presents a highly sensitive THz sensor for detecting biological samples, with a small footprint and high sensitivity. The sensor's sensitivity was estimated using absorption characteristics, and it was evaluated for various materials and biomedical samples, showing an average sensitivity of 1936 GHz/RIU.