Application of differential phase measurement technique to surface plasmon resonance imaging sensors

In this paper, a differential phase imaging technique applied to optical surface plasmon resonance (SPR) sensors is presented. The technique makes use of the s-polarisation as the reference beam to interfere with the p-polarisation, of which the phase has a close relationship with the change of SPR conditions at the sensor surface. As a trial experiment, the SPR phase shift between water and air has been measured. Our results suggest a measurement accuracy of 5/spl times/10/sup -2/ rad.