A wide variety of fiber-optic sensors based on fluorescence have been developed for important applications in the last few years. Unfortunately, no systematic study describing an optimized design has appeared. A fiber-optic fluorescence sensor testbed was constructed, and different optical designs and components were compared for sensitivity in detecting fluorescence. Different beamsplitters, launching objectives, filters, detectors, and configurations were evaluated on the basis of their measured signal-to-noise ratio in detecting 100 picomolar fluorescein. Sources of noise and background were identified, and generally applicable means for minimizing them are described.
Richard B. Thompson, Michael Levine, and Lynne Kondracki, "Component Selection for Fiber-Optic Fluorometry," Appl. Spectrosc. 44, 117-122 (1990)