Ju-Yi LEE^* and Wu-Sheng GU

Department of Mechanical Engineering, National Central University, Chungli 32054, Taiwan

(Received August 15, 2012; Revised November 15, 2012; Accepted December 19, 2012)

A differential detection technique combined with a surface plasmon resonance technique is proposed for refractive index variation measurement. The experimental results demonstrate that our system can attain a resolution of 1.2× 10^-5 RIU (refractive index unit). In addition, a method for two-dimensional detection of the refractive index variation is demonstrated. The system is free from the influence of optical source fluctuation, and can improve the measurement sensitivity.

Key words: refractive index, surface plasmon resonance, differential detection, biosensors, two-dimensional detection

^*E-mail address: juyilee@ncu.edu.tw