Beam-angle-scanning surface plasmon resonance sensor for rapid, high-precision sensing of refractive index and bio-molecules

Surface plasmon resonance (SPR) sensors are powerful tools for optical sensing of refractive index (RI) and bio-molecules due to their high sensitivity. In this article, we demonstrate a beam-angle-scanning SPR system using a combined galvanometer mirror and relay lens optics. Use of a photodetector in the galvanometer mirror scanning of the incident beam angle enables both high precision and rapid data acquisition. RI resolution of 2.306×10 −5 refractive index unit (RIU) and RI accuracy of 8.984×10 −5 RIU were achieved at a data acquisition rate of 100 Hz. Furthermore, we performed real-time monitoring of the avidin-biotin antigen-antibody reaction. The results show the high potential of this beam-angle-scanning SPR system.