OPTICAL PHASE-SHIFT DETECTION OF SURFACE-PLASMON RESONANCE

A heterodyne optical measurement system for studying the phase shift o f surface plasmon resonance (SPR) is presented. The system utilizes a frequency-stabilized Zeeman laser as a detection light source and is s uitable for real-time phase measurement in SPR-sensing applications. T he phase shift in an angular dispersion SPR excitation setup was measu red ranging from +180 degrees to -120 degrees around the SPR excitatio n region. The experimental results fit well with the theoretical analy sis. Compared with the reflection coefficient variation that is widely investigated in SPR studies, phase shift is estimated to provide a hi gher sensitivity to sensor systems and more information about the reso nance phenomenon. (C) 1998 Optical Society of America.