Noise reduction in high-specificity sensor based on surface plasmon resonance

Abstract

A large variety of optic methods has been used in the chemical sensors and biosensor including spectroscopy (luminescence, phosphorescence, fluorescence...), interferometry (white light interferometry, modal interferometry in optical waveguide structures) and surface plasmon I resonance. In these sensors, by mean of methods based on the measure of the variations of optic characteristics as the refraction indexes or emission/absorption spectra, the biochemical compound properties are calculated.Two decades ago, the first application of surface plasmon resonance phenomenon (SPR) was presented, since then instrumentation systems for the characterization and quantification of biomoleculars interactions have been developed.The high specificity surface plasmon resonance sensor presented hereby is based on two photodiode arrays, one for reference measurement and other for the selective detection. This report shows several solutions that contribute to the optimization of the design of acquisition electronics that must deal with weak signals in noisy electronic enviroments. The noise minimization in electronic circuits versus digital signal processing limitations is the basis of the design improvement. This work solves the inherent problems in the design of circuits where photodiodes arrays and analog multiplexer are used.