Multimode waveguide mode surface plasmon coupling: a sensitivity and device realizability study

Abstract

The coupling of p-polarized waveguide modes into waveguide-surface plasmon coupled modes is a promising concept to combine the features of propagating waveguide modes with the resonant field enhancement of surface plasmons and the unique possibility to functionalize the metal surface by self-assembled monolayers (SAMs) via sulfur chemistry. Recently we have demonstrated a waveguide device which allows to couple two TM waveguide modes to the surface plasmon and were able to characterize a new binding matrix with respect to the thickness and the refractive index. The noise and the sensitivity of this device needs further improvement. Therefore we present a sensitivity and device realizability study in order to optimize the technique of multimode waveguide mode surface plasmon coupling for the determination of the thickness and the refractive index of ultrathin layers binding to a metal surface.