Surface plasmon resonance prism coupler for enhanced circular dichrosim/birefringence sensing

Abstract

A novel method for surface plasmon resonance (SPR) enhanced circular dichroism (CD), circular birefringence (CB), and degree of polarization (Dep) detection is proposed using Stokes-Mueller matrix polarimetry technique. The validity of the analytical model is confirmed by means of numerical simulations, and the simulation results show that the proposed detection method for CB and CD has a sensitivity of 10 -5 RIU and 10 -4 RIU (refractive index unit) for refractive indices in the range of 1.3~1.4, respectively. The practical feasibility of the proposed method is demonstrated by the experimental results for detecting the CB/CD/Dep with the glucose-chlorophyllin compound samples contained polystyrene microsphere particles. It is shown that the extracted CB value decreases linearly with glucose concentration over the considered range while the extracted CD value increases linearly with the chlorophyll concentration over the considered range. In general, the results obtained in this study show that the measured CB and CD response is highly sensitive to the polarization scanning angle. Consequently, the potential of Stokes-Mueller matrix polarimetry for highresolution in CB/CD/Dep detection is confirmed.