Spectral analysis for SPR sensor with monolayer metal film

In order to explore the key factors of the SPR effect, such as sensitive material, thickness of sensitive metal film, incident angle and wavelength, especially the affection of the incident light wavelength on the modulated reflectivity, calculations and analyses are carried out in this paper. Simulation results show that Ag has the lowest reflectivity when the incident light with shorter wavelength in visible wave band, Au has the lowest reflectivity with red light, and Cu has the best effect from 600 nm to infrared band. The ranges of thickness measurement for thin films can be obtained when the light source wavelength and incidence angle are fixed with the adopted metal sensitive material. Moreover, there is a special range of incidence angle that can put up a significant SPR effect phenomenon when there are definite metal films and wavelength of incident light.