High-sensitivity refractive index sensor: a surface lattice resonance platform based on periodic gold nanoparticle array

A high-sensitivity refractive index (RI) sensor based on the surface lattice resonance of periodic gold nanoparticle array is proposed. The influence of sensor structural parameters on the extinction spectrum is systematically investigated. The physical mechanism behind the extinction peak is discussed by the electric field simulations. The optimal structural parameters are determined by calculating and analyzing key sensing performance metrics, namely sensitivity and figure of merit (FOM). In the considered RI range, the optimal sensor exhibits a sensitivity of 562.42 nm RIU −1 and a FOM of 54.38 RIU −1 . Notably, in a specific subrange, the sensitivity and FOM can reach maximum values of 600 nm RIU −1 and 60.61 RIU −1 , respectively.