Surface plasmon resonance enhanced transverse magneto-optical Kerr effect and the detection performance of nanopore arrays

Abstract

Abstract The introduction of a magnetic component to the surface plasmon resonance (SPR) structure to form a magneto-optical surface plasmonic resonance (MOSPR) detector is an effective method for enhancing the detection limit for small molecules at low concentrations. This is important for biosensing, early disease diagnosis, drug discovery, and the detection of contamination in solutions and gases. In this study, a MOSPR crystal composed of a Co6Ag94 slab covered by a subwavelength periodic square array of gold (Au) nanopores was designed to theoretically examine the mechanism by which MOSPR crystals detect glucose concentrations through the transverse magneto-optical Kerr effect (T-MOKE). Owing to the excitation of SPR at the interface between the glucose solution and Au film, a Fano-like sharp T-MOKE spectrum with a narrow linewidth and a high amplitude was obtained, thus producing a high sensitivity of 159° RIU−1 and a high figure of merit (FOM) of the order of 103 RIU−1. This corresponds to a glucose detection limit of 0.0066 g/ml, which is more accurate than that previously reported. This design provides an alternative method for detecting analytes’ concentrations in aqueous environments.