Investigation of a periodically segmented waveguide Fabry-Pe/spl acute/rot interferometer for use as a chemical/biosensor |
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Authors: | Kinrot N. Nathan M. |
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Affiliation: | Dept. of Phys. Electron., Tel-Aviv Univ., Ramat Aviv, Israel; |
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Abstract: | We present a periodically segmented waveguide Fabry-Pe/spl acute/rot interferometer (PSW-FPI) intended to be used for tagless real-time chemical/ biological sensing through bulk-material interaction. The differential sensor detects changes in the refractive index (RI) of a sample regardless of its absolute RI value. Experiments with a series of sucrose solutions of various concentrations are compared with theoretical results, and a very good match is found between the two. The theoretical sensitivity limit for a 50-dB-signal-to-noise-ratio (SNR) measurement system is estimated as /spl delta/n=3/spl middot/10/sup -7/. For a 29-dB-SNR measurement system, a measured sensitivity limit of /spl delta/n=4/spl middot/10/sup -5/ is comparable with the previously reported sensitivities of label-free real-time optical biosensors (2/spl middot/10/sup -5/-5/spl middot/10/sup -5/). However, the total required sensing length (720 /spl mu/m) of our PSW-FPI sensor is much shorter than that of the previously reported devices (9-20 mm). |
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