Study of prism surface plasmon resonance effect based on dielectric-aided layer

Abstract

A prism surface plasmon resonance (SPR) incentive model based on the dielectric-aided layer structure is studied. The model consists of four structure layers: prism-dielectric-aided layer-gold-environmental media. According to the thin film optics and waveguide theory, the excited mechanism and modulation characteristic of SPR effect are explored based on resonance composite film composed of dielectric-aided layer and gold film. Numerical simulation is conducted on the relation of layer thickness, film dispersion characteristics and resonance energy transfer by the finite difference time domain method. Thereby, the wavelength modulation prism dielectric-aided layer SPR excitation system is also developed. Results show that with the same refractive index of liquid, the SPR resonance spectrum of dielectric-aided layer incentive model shifts to the longer wavelength region and the resonant halfwave width is wider than the spectrum of common Kretschmann incentive model based on prism-gold-environmental media. With increasing refractive index, the SPR resonance spectrum redshifts, and its sensitity is 75% higher than the common incentive model. The designed model can effectively improve the sensitivity of the prism surface plasmon resonance effect, and in the areas such as high sensitivity detection, new types of optical filter, the modulator and other fields the SPR technology may provide a theoretical and practical basis.