CONTROL OF THE DYNAMIC-RANGE AND SENSITIVITY OF A SURFACE-PLASMON RESONANCE BASED FIBER OPTIC SENSOR

The refractive index sensitivity and dynamic range of a recently developed fiber optic based surface plasmon resonance sensor have been investigated. The sensor response was studied using a set of aqueous refractive index standards. The sensitivity to refractive index was found to be between 5.0 x 10(-4) and 5.0 x 10(-5) index of refraction units. The dynamic range of an unmodified sensor was between 1.25 and 1.40 index of refraction units. The dynamic range was tuned for ranges between 1.00 and 1.40 index of refraction units with the addition of thin high refractive index overlayer films. This range is significant since it includes both gas and aqueous chemical sample refractive indices. The upper limit of the refractive index dynamic range was extended to 1.70 by use of a sapphire fiber core material.