A heterodyne optical measurement system for studying the phase shift of surface plasmon resonance (SPR) is presented. The system utilizes a frequency-stabilized Zeeman laser as a detection light source and is suitable for real-time phase measurement in SPR-sensing applications. The phase shift in an angular dispersion SPR excitation setup was measured ranging from +180° to -120° around the SPR excitation region. The experimental results fit well with the theoretical analysis. Compared with the reflection coefficient variation that is widely investigated in SPR studies, phase shift is estimated to provide a higher sensitivity to sensor systems and more information about the resonance phenomenon.
© 1998 Optical Society of America
Original Manuscript: September 11, 1997
Revised Manuscript: November 24, 1997
Published: April 1, 1998
Shuai Shen, Tong Liu, and Jihua Guo, "Optical phase-shift detection of surface plasmon resonance," Appl. Opt. 37, 1747-1751 (1998)