Optimal design of surface plasmon resonance films structure

Kretschmann surface plasmon resonance (SPR) films structure is one of the most important parts of probe induced surface plasmon resonance coupling nanolithography (PSPRN). The film characteristic matrix method is used to calculate the transmission coefficient and the reflectivity of the layers for optimal design of single-, two- or three-films structure of PSPRN. Optimal results for the selected film materials are obtained at the wavelength of 514.5 nm. For single film structure, the optimal thickness of Ag film is 46 nm. The optimal thickness of the Ag film is 24 nm and the AgO_x film is 95 nm for two-film structure. For three-film structure, the optimal result is that the thickness of Ag film is 44 nm, SiO₂ film is 180 nm, and AgO_x film is 10 nm. Furthermore, it is presented that the material with small refractive index and low absorption coefficient is more effective as the recording layer.