Solute concentration sensing in two aqueous solution using an optical metamaterial sensor

Highlights: • Plasmonically induced transparency is analyzed in a metamaterial structure. • Asymmetrical geometry is required for PIT observation. • Sensing application is investigated for the proposed Nano structure. • Solute concentration is calculated for two aqueous solution NaCl solution and ethanol in water. • The sensitivity for NaCl solution is about $77\frac{\mu m}{mol/d{m}^3}$, and for ethanol solution is about $87.7(GHz/RIU)$. An optically semiconductor metamaterial sensor for solute concentration sensing is designed based on plasmonically induced transparency (PIT) effect. The concentration of two aqueous solutions, NaCl and ethanol in water solutions are investigated using the proposed optical sensor. The optimization process to find the best geometrical size for the antennas and also the material thicknesses cause to have a very high sensitivity for two aqueous sensor so that the maximum sensitivity for NaCl solution is approximately 224 $\frac{\mu m}{RIU}$which is a high value in comparison with the reported values in literature and the optical sensitivity of ethanol-water concentration is $27.2\frac{\mu m}{RIU}$which is an ultra-high value compared to literature reported values. The values of $1.5\times {10}^{-2}$and $4.7\times {10}^{-2}$ in refractive index unit are obtained for limit of detection and quantification, respectively.