Compact and Ultrasensitive Terahertz Metamaterial for Tumor Detection Based on Refractive Index Sensing

A compact and ultrasensitive metasurface-based angle insensitive single-band terahertz (THz) sensor comprising of thin gold mirror-symmetric dual circular E-shaped resonator (MS-DCESR) unit cell was investigated for the human brain tumor tissue detection through refractive index. The overall metamaterial (MM) configuration results in ultrahigh sensitivity of 50 THz/RIU with a high Q-factor of 25.77 due to a Full-Width-Half-Maximum (FWHM) of 0.045 THz. Also, the result reveals a maximum figure of merit (FOM) of 1111.11 RIU-1. The overall volume of the sensor was estimated to be 26460 μm3. Unlike previously THz MM-based sensors, the proposed design combines compact geometry with sharp light-matter interaction features to achieve ultrasensitive refractive index detection. The reported configuration is therefore highly suitable for label-free and noninvasive neurological sensing. Also, these results validate the effectiveness of the designed sensor is a promising candidate for future early brain tumor detection and other biomedical sensing applications.