Measurement of amino acid solutions based on novel optical effects

Abstract

We studied the nonlinear optical properties of a square split-ring structure of magnetic metamaterials and the mechanism by which a non-centrosymmetric silver structure generates the second harmonic within the near-infrared band. We also analyzed the effect of the silver structure on the second harmonic and applied the silver structure in an air cavity-silver-glass structure, which is an insulator-metal-insulator structure, for sensing. By identifying the effect of different refractive indexes on the transmission spectrum, we obtained the intrinsic relation between the refractive index and the wavelength at which the second harmonic is excited. The experimental results indicate that with the growth of the refractive index, the second harmonic has an evident red shift and that by changing the shape and split width of the silver structure, the sensitivity is significantly improved, measurement of amino acid solutions up to 1007.2 nm/RIU. This study brings new insight into the application of second harmonics with nonlinear effects in the sensing field.