High FOM Plasmonic Nanosensor for Blood Biomolecule Detection

In this paper, a plasmonic refractive index sensor is proposed for label-free sensing of biomolecules present in blood. The sensor design is conceptualized on a metal-insulator-metal waveguide setup consisting of a microring and a plus-shaped enclosed within a U-shaped resonator separated by a linear rectangular bus waveguide. The transmittance characteristics of the proposed design are studied using the finite difference time domain methodology. The transmittance curve results in quintuple Fano resonances with sensitivities of 1152.6 nm/RIU (refractive index unit), 1116.6 nm/RIU, 1182.2 nm/RIU, 1438.6 nm/RIU and 2109.7 nm/RIU at resonant wavelengths of 1.055 \(\mu \) $\mu$ m, 1.146 \(\mu \) $\mu$ m, 1.223 \(\mu \) $\mu$ m, 1.494 \(\mu \) $\mu$ m, and 2.12 \(\mu \) $\mu$ m, respectively. Moreover, other performance parameters are also investigated including figure of merit, quality factor, and detection limit which comes out at a value of 91.3 \(RIU^{-1}\) $RI{U}^{-1}$ , 91.7, and 0.010, respectively. Furthermore, the sensor performance is investigated with respect to the detection of multiple biomolecules present in the blood. The highest sensitivity of 2180 nm/RIU is obtained with respect to analyte sensing.