Surface plasmon resonance biosensing by electro-optically modulated attenuated total reflection

This study presents a surface plasmon resonance biosensing technique based on electro-optically modulated attenuated total reflection. The initial wavevector of the light for exciting surface plasmons is specified by setting the incident angle and is then modulated by electro-optic effect. The light power which is attenuated-total-reflected from the metal/dielectric interface is correspondingly electro-optically modulated. Its variation with the applied voltage is utilized to determine the analyte concentration. In the biosensing process, the incident angle determines the initial position of the operation point and thus the detection sensitivity. The presented technique has the features of resolution tunability and sensitivity tunability under various base indices of sensing layer or analyte solution for optimal operation. In this work, the effects of the incident angle, the Au-film thickness, and the ridge width on the detection sensitivity are also discussed.