Sensitivity improvement of the surface plasmon resonance optical sensor by using a gold-silver transducing layer

It is well established that the surface plasmon resonance (SPR) optical sensor based on a metal-dielectric configuration can provide high sensitivity for many applications such as chemical and biological sensing. In fact the gold-dielectric configuration is most commonly used in the SPR sensor because of the fact that the thin gold layer can provide stable performance and good chemical resistance. In this paper, the characteristics of spectral SPR sensors that use composite silver/gold films for the transducing layer have been studied by using Fresnel formulas. Our simulations indicate that the optimal layer configuration for spectral SPR sensors should be gold(2 nm)-silver(48 nm)-dielectric for achieving best sensitivity.