Hybrid plasmonic microring resonator for sensing of the concentration of water-soluble CaCl۲ electrolyte

In this paper, the design and analysis of a label-free biosensor based on microring hybrid plasmonic resonator with a silicon ring with an outer radius of ۹۴۰ nm and a ۵۴۵ nm gold disk in the center of silicon ring, in the third telecommunication window to sense the concentration of water-soluble CaCl۲ electrolyte is presented. The simulation results obtained using three-dimensional FDTD show that the sensitivity and numerical results obtained for the sensing of CaCl۲ electrolyte with concentrations of ۰ to ۲۵% in water solution, respectively, are equal to ۱۸۹.۹۳ (nm / RIU) and ۱۲.۵۹ (۱ / RIU). Comparing the results of the proposed sensor with the previous work, which has four times more footprint, shows that the structure's sensitivity has increased. Also, to study the use of plasmonic hybrid structure in improving the sensor's sensitivity, a silicon microring sensor without a gold disk was designed and compared. The results show that the plasmonic hybrid structure enhances the sensitivity compared with the photonic structure by ۱۶ percent without increasing the dimensions, which is compatible for integration.

کلیدواژه ها:

ring resonator ، hybrid plasmonic ، biosensor ، refractive index sensor ، CaCl۲ sensor