<title>SPR fiber optic microsensor: system and applications</title>

Abstract

An improved refractive index microsensor based on surface plasmon resonance (SPR) for fine scale measurements in aquatic environments is presented. Furthermore this sensor should serve as a platform for different applications. In the first place refractive index measurements in marine environments have been performed to characterize the light conditions around photosynthetically active organisms. By scalar irradiance microprobes the light intensity can be investigated at a spatial resolution of 100micrometers . The presented sensor for refractive index achieves a spatial resolution better than 1mm. It covers a range of 1.30 and 1.38 refractive index units (RIU) with an accuracy of 5x10^-4 RIU. Due to this accuracy, the miniaturized geometry and the simple preparation the sensor can serve as a platform for chemo- and biosensors with a high spatial resolution and fast response. Therefor a suitable sensitive layer that converts the specific analyte concentration into a refractive index change can be deposited onto the gold surface. For that purpose swellable polymer microspheres are currently investigated. The sensor characteristics, measurement system, and applications are presented.