Multiregion Surface Plasmon Resonance Fiber-Optic Sensors

Abstract

The first report of the effect of surface plasmon resonance (SPR) was made by Wood in 1902 when he noticed the absence of light in narrow spectral bands from a diffraction grating. SPR spectroscopy has now been applied to a number of analytical problems due to its high sensitivity to variations in the electronic nature of a surface. For SPR measurements in a laboratory setting where the geometry of the optical system can be conveniently constructed, the Kretschmann configuration is optimum due to the narrow resonances measured. An optical-fiber-based SPR sensor is normally made from a single fiber that has its cladding etched down to the optical core of the fiber over a known section of length. This chapter develops the background mathematics that predicts SPR in a planar geometry. These models were then expanded to a single-ended cylindrical geometry that can be made into a practical single-ended fiber-optic probe.