A simple and inexpensive surface plasmon resonance setup for phase detection using rotating analyser ellipsometric method

In the present work we have developed an inexpensive surface plasmon resonance (SPR) setup for the detection of phase modulation. The developed setup is based on Kretschmann's prism based configuration and uses the principle of rotating analyser ellipsometry. Angular modulation and phase modulation of a self-assembled monolayer of 1-Octanethiol on an Au film surface have been investigated with the developed setup. A sensitivity of 10^-4 refractive index unit (RIU) for angular modulation and 10^-6 RIU for phase modulation was obtained. Although the obtained sensitivity is an order of magnitude lower compared to other angle and phase modulation based studies, the phase modulation still provides a sensitivity two orders better than that of angular modulation. The advantage of the developed setup is that it uses inexpensive optical components yet provides a good sensitivity for static SPR measurement.