Phase detection sensitivity enhancement of surface plasmon resonance sensor in a heterodyne interferometer system.

We propose a method of rotating the analyzer in front of the photodetector in a heterodyne interferometer system to implement optical phase shift and detection sensitivity enhancement of surface plasmon resonance (SPR) sensors. When the analyzer is rotated to shift the phase curve to be near the phase jump point, the phase detection sensitivity of the SPR sensor can be greatly enhanced. Theoretical calculations of a prism-coupled SPR device were performed using this method. Experimental result using an electro-optic heterodyne interferometer is reported.