Tailoring the parameters of nanohole arrays in gold films for sensing applications

Subwavelength hole arrays in metal films have the potential to exhibit narrow and high refractive index (RI) sensitive transmission features. We have previously demonstrated that such features can arise from the coupling between Wood anomalies (WAs) and surface Plasmon polaritons (SPPs) on opposite sides of the metal film, the "WA-SPP" effect. Rigorous coupled-wave analysis (RCWA) calculations on a 2D model, which are shown to give WA-SPP features very similar to that of 3D Finite-Difference Time-Domain (FDTD) calculations, are performed to determine how system parameters influence the strength of the WA-SPP effect. Herein we show that the optimum values for the film thickness and hole diameter are 45 and 175 nm, respectively.