Theoretical comparison of sensitivity enhancement of various metals based nearly guided wave surface plasmon resonance biosensors designed by genetic algorithm

In this paper, the comparative study of sensitivity of NGWSPR biosensor with Au, Ag, Cu and Al is presented. To achieve high sensitivity, the thickness of each layer in the proposed biosensor is optimized using genetic algorithm (GA). A constraint condition of reflectivity at resonance angle is used in the merit function (MF) of GA to realize large depth of dip. Using this method, NGWSPR biosensors with Au, Ag, Cu and Al are designed and analyzed. The sensitivity of designed Ag based NGWSPR biosensor is up to 289 °/RIU when using TiO₂ as the dielectric, which is 31.83%, 24.91% or 61.94% higher than the sensitivity of designed Au, Cu or Al based one. We believe our work is important because it compares the largest sensitivities of NGWSPR biosensors with different metals, and be helpful for highly sensitive biosensors development.