Particle swarm optimizer for the surface plasmon resonance effect on metal gratings.

In this work, the spectral dependence of optimum parameters of the surface plasmon resonance (SPR) effect on metallized sinusoidal diffraction gratings, under normal incidence, was determined using the particle swarm optimization method. The method was chosen due to its simplicity and effectiveness in providing reliable results, relative to direct search or gradient methods. The Rayleigh's hypothesis, which restricts the analysis to the case of shallow gratings, is used to model the diffracted fields across the interface between the sensing medium and metal.