A universal model of surface plasmon resonance characteristics for isotropic multilayer films

A theoretical model is presented for multilayered surface plasmon resonance sensors composed of isotropic materials. In the framework of optical transmission theory in multilayers, by solving Helmholtz equations, the expression of electromagnetic field distribution inside multilayered structures is established. This model is applied in the simulation of surface plasmon resonance characteristics of single Au layer, bilayer Co/Au and trilayer Au/Co/Au respectively. The calculated reflectivity curves are in excellent agreement with the experimental results. The simulated field distribution inside layered structures give an explicit explanation to the variations of reflectivity as a function of incident angle. Thus, the presented model can be used as an analytical tool in the format of SPR sensors.