Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2004
Publication Date: 11/15/2004
Citation: Chen, G. 2004. Luminescence imaging as a tool in profile optimization of taper quartz-rod waveguides. Meeting Abstract.
Technical Abstract: In evanescence field luminescence sensing, the geometry of the waveguide sensing zone plays an important role in both coupling of excitation energy into evanescent field and reciprocal collection of luminescence signal. A tapered optical fiber has been proven to outperform cylindrical fibers in both aspects by V-number conversion in the taper zone. Since evanescent-field effects are intrinsically very weak, sensitivity enhancement is expected by dimension scale-up and sensing zone profile optimization. In this study, tapered waveguides were made of 6 mm quartz rod by flame drawing. An important goal in optimization is to couple light into evanescent field efficiently with minimal leakage into the bulk. Luminescence imaging provides the capability to pinpoint the location and the amplitude of light leakage, so it was used as an effective tool in taper profile optimization. The finished waveguides were installed in a flow-through cell specifically designed to implement this sensing scheme; and their performance was evaluated by time-resolved luminescence (TRL) using oxytetracycline as a model analyte. Theoretical discussions were supported by imaging and spectroscopic data. The techniques and results of this study can be applied to the development of fiber optic sensors.