Optical sensing of biomolecules using microring resonators |
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Authors: | Yalcin A Popat KC Aldridge JC Desai TA Hryniewicz J Chbouki N Little BE Oliver King Van V Sai Chu Gill D Anthes-Washburn M Unlu MS Goldberg BB |
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Affiliation: | Boston Univ., MA, USA; |
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Abstract: | A biosensor application of vertically coupled glass microring resonators with Q/spl sim/12 000 is introduced. Using balanced photodetection, very high signal to noise ratios, and thus high sensitivity to refractive index changes (limit of detection of 1.8/spl times/10/sup -5/ refractive index units), are achieved. Ellipsometry and X-ray photoelectron spectroscopy results indicate successful modification of biosensor surfaces. Experimental data obtained separately for a bulk change of refractive index of the medium and for avidin-biotin binding on the ring surface are reported. Excellent repeatability and close-to-complete surface regeneration after binding are experimentally demonstrated. |
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