Highly Sensitive Terahertz Metamaterial Absorber with Enhanced Q-Factor and FOM for Cancer Cell Detection

This work introduces an innovative design of a polarization-insensitive, narrowband metamaterial absorber (MMA) sensor specifically utilized for the detection of malignant cells. The sensor under consideration functions within the terahertz (THz) frequency range of $4.8-6.5 \mathrm{THz}$, demonstrating significantly increased absorbance and improved performance parameters. Equipped with a metal-insulator-metal (MIM) configuration including gold and PTFE materials, the absorber exhibits almost complete absorption rates at particular resonance frequencies, attaining a 95% absorption at 4.52 THz and a $99.96 \%$ absorption at 5.78 THz. The simulation results obtained from the CST software provide comprehensive descriptions of the electric field, magnetic field, and surface current distributions. These findings clearly illustrate the effectiveness and lack of sensitivity to polarization of the sensor. The work investigates using this mixed-mode amplitude (MMA) for detecting cancer cells by quantifying shifts in absorption resonance peaks resulting from variations in refractive indices. An analysis of the performance parameters of the suggested sensor, such as sensitivity, quality factor (Qfactor), and figure of merit (FOM), reveals its superiority over existing designs. The Q -factors are measured at 251.11 and 321.11, the sensitivity at 3 and $2 \mathrm{THz} /$ RIU, and the FOM at $166.67 \mathrm{RIU}^{-1}$ and $111.11 \mathrm{RIU}^{-1}$. The findings suggest that the sensor exhibits excellent efficacy in biomedical applications, namely in the identification of early-stage cancer.