Highly sensitive refractive index sensor by floating nano-particles in the solution for the detection of glucose/fructose concentration

In this research, an optimum design is proposed for better utilization of field resonance. More interaction of the field formed around nano-particles with a solution, which has refractive index variations, can substantially increase the sensitivity of the plasmonic biosensors. More interaction could be provided by floating nano-particles in the solution. The proposed structure, which has peak plasmonic resonance, has better light sensing features in comparison to similar non-floating structures. While without floating nano-particle, sensitivity is 265.8 nm/RIU with the realization of the full floating nano-particles, the sensitivity of the structure with elliptic disc and circular disc nano-particles are 574.2 nm/RIU and 425 nm/RIU, respectively. Full width at half maximum (FWHM) of the structure with elliptic disc and circular disc nano-particles are 57.4 nm and 49.4 nm, respectively. In presence of meshed SiO2 network and pseudo-floating form, sensitivity and FWHM of the structure are 504 nm/RIU and 58.4 nm for elliptic discs and 372 nm/RIU and 49.9 nm for circular discs, respectively.