In this study an alternative method based on surface plasmon resonance is proposed for in-situ monitoring of variation in the refractive index of a test sample A wavelength modulated light source and an unequal-path length optical configuration heterodyne interferometer are used to detect the phase difference change which can then be used to estimate the change in the refractive index of a test sample The experimental results demonstrate a phase stability of 0 02 The resolution power of the refractive Index is 1 5 x 10(-6) RIU This method has several advantages over previously used methods such as simple optical setup easier operation in real time and low cost (C) 2010 Elsevier BV All rights reserved
