Transducer based on surface plasmon resonance with thermal modification of metal layer properties

Abstract

With the purpose to improve such service characteristics of transducers on the basis of the surface plasmon resonance (SPR) as the sensitivity and stability, we have analyzed the influences of a structure and a relief of the surface of polycrystalline gold films, which are determined by technological conditions of their production and by the low-temperature annealing, on their optical characteristics, namely, the coefficients of refraction, extinction, and light scattering. It is shown that the mechanism of enhancement of the sensitivity of an SPR-based transducer consists in a decrease in the coefficient of extinction of a metal film, as the annealing temperature increases. At the optimum annealing temperature (120°C), we observed the smoothing of a small-scale roughness of the gold film surface, which decreases the scattering of plasmons, favors the defectless formation of protective nano-sized layers, and enhances the sensitivity and stability of the operation of SPR-based transducers.