Research Paper: The Phase Sensitivity Enhancement of the Surface Plasmon Resonance Sensor in the Common-path Polarization Heterodyne Interferometry

Abstract

Surface plasmon resonance (SPR) is the excitation of cumulative charge oscillations in the metal-dielectric interface. Of the various surface plasmon-based measurement methods, phase-based measurement methods are the most accurate and sensitive. The wave phase can be measured with appropriate accuracy by various interferometry methods. The common path polarization heterodyne interferometry method compared to the conventional heterodyne method has the advantage of stability against changes in the ambient due to vibration and temperature changes. Increasing sensitivity has always been considered as one of the important challenges in designing and manufacturing various types of SPR-based sensors. In this study, after a theoretical investigation of enhancement of the phase sensitivity due to the addition of a quarter-wave plate in the common path polarization heterodyne interferometer, the SPR phase change in the standard common path polarization heterodyne interferometer arrangement is measured. Comparing the results with the results of the modified setup proves the phase sensitivity enhancement. Experimental results show a sensitivity enhancement of at least 3.5 times.

Keywords

• surface plasmon resonance
• increased phase sensitivity
• phase measurement
• common-path polarization heterodyne interferometry (cphi)