Multi-resonance plasmonic MIM refractive index biosensor for disease/biomolecules detection

This paper describes a plasmonic metal insulator metal based refractive index sensor for biomolecules detection. This sensor utilizes a ring resonator coupled to a waveguide which results in the generation of multiple resonance modes in the device's transmittance spectrum. The ring resonator configuration demonstrates a useful approach for tunable sensing of biomolecules and refractive index sensing applications. The simulations are carried out using the three-dimensional finite element method. The proposed device detects diseases such as malaria and chikungunya by measuring the wavelength shift in its multiple resonance modes in response to changes in the refractive index of the ring resonator. The device shows a sensitivity of 4000nm/RIU for malaria detection and 6000nm/RIU for chikungunya detection for the first resonant mode. Furthermore, this device has shown good quality factor as well as acceptable figure of merit for malaria and chikungunya detection. The maximum quality factor for malaria and chikungunya detection is 44.57 and 70, respectively. Additionally, for chikungunya, the maximum figure of merit of 71.2 is obtained for infected and normal red blood cells for its third resonant mode, while the maximum FOM for malaria detection is 66.66. Furthermore, the device has demonstrated its potential as a cholesterol concentration detector, with a sensitivity of 4000nm/RIU in its first resonant mode. The highest figure of merit for cholesterol concentration is calculated as 95.23. In the end, device optimizations are conducted to evaluate how variations in geometric parameters influence transmittance and resonance wavelength. The device's ability to detect refractive index variations between 1.0 and 1.56 indicates its substantial potential for refractive index sensing and biosensing applications.