Surface plasmon resonance biosensor based on electro-optically modulated phase detection.

A novel electro-optically modulated surface plasmon resonance (EOMSPR) biosensor based on phase detection by collinear heterodyne interferometry is presented. Its operation is by means of modulating the SPR-induced phase variation by electro-optic effect. Because the relation between the phase change and the applied voltage is highly sensitive to analyte properties, the linear regression slope of this relation can be used in the analyte detection. The detection characteristics of this EOMSPR biosensor are measured, and their dependences on waveguide width and gold-film thickness are discussed. This novel EOMSPR biosensor has attractive features, such as compactness, resolution tunability, and noise reduction.