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ABSTRACT: We present a fully planar integrated optical approach to single-molecule detection based on microfabricated planar networks of intersecting solid and liquid-core waveguides. We study fluorescence from dye molecules in liquid-core antiresonant reflecting optical waveguides, and demonstrate subpicoliter excitation volumes, parallel excitation through multiple pump waveguides, and single-molecule detection sensitivity. Integrated silicon photonics combined with single-molecule detection in solution create a compact, robust, and sensitive platform that has applications in numerous fields ranging from atomic physics to the life sciences.
Optics Letters 08/2006; 31(14):2136-8. · 3.40 Impact Factor
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ABSTRACT: We present the characterization of the optical properties of integrated antiresonant reflecting optical (ARROW) waveguides with arch-shaped liquid cores. Optical mode shapes and coupling, waveguide loss, and polarization dependence are investigated. Waveguide loss as low as 0.26/cm with near-single-mode coupling and mode areas as small as 4.5microm2 are demonstrated. A detailed comparison to ARROW waveguides with rectangular cores is presented, and shows that arch-shaped cores are superior for many applications.
Optics Express 01/2006; 13(26):10564-70. · 3.59 Impact Factor
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ABSTRACT: We report loss improvement and fluorescence detection in integrated antiresonant reflecting optical waveguides with liquid cores. The minimum waveguide loss is reduced to 0.33/cm by compensating for thickness variations in the fabrication process. We demonstrate fluorescence detection from as few as 490 molecules in a 57 pl core using these optimized waveguides. We measure angular fluorescence collection factors as high as 15% per facet in good agreement with theory. This demonstrates the potential of integrated hollow-core waveguides as optical sensors for single-molecule spectroscopy.
Applied Physics Letters 11/2005; 87(21):211111-211111-3. · 3.84 Impact Factor
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ABSTRACT: This paper provides a structural analysis of hollow silicon dioxide micro-channels that have applications in microfluidics and photonics. A specific fabrication method is highlighted that uses aluminum as a sacrificial material. Possible causes of failures that occur during fabrication are investigated, and internal pressure produced during the fabrication process is identified as the most likely failure mechanism. Three models are developed for the fabricated micro-channels. Models based on elementary beam theory and energy methods verify a nonlinear finite element model. Design parameters in the finite element model are varied to investigate which have the greatest effect on structural strength and ultimate failure. Experimental results are used with the model to estimate the pressure at failure. Finally, based on the model and experimental results, a rule is developed for the design of the hollow micro-channels described in the paper: maintain the width-to-thickness ratio below 35.
Journal of Micromechanics and Microengineering 02/2005; 15(4):720. · 2.11 Impact Factor
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ABSTRACT: We present integrated antiresonant reflecting optical (ARROW) structures with hollow cores as a new paradigm for optical sensing of gases and liquids. ARROW waveguides with micron-sized hollow cores allow for single-mode propagation in low-index non-solid core materials where conventional index guiding is impossible. We review design, fabrication and optical characterization of these devices for possible applications in chemical sensing, single molecule fluorescence and Raman spectroscopy, flow cytometry, and pollution monitoring of picoliter to nanoliter volumes. We describe how to determine and control the waveguide loss and dispersion of the ARROW waveguides and design optimization for realistic structures that are compatible with the fabrication constraints. The technology to realize hollow-core waveguides using conventional silicon microfabrication and sacrificial core layers is discussed. We present the first demonstration of waveguiding in integrated ARROW waveguides with both hollow and liquid cores. Single-mode propagation with mode areas as small as 6mm2 and volumes down to 15 picoliters is observed and the loss characteristics of the waveguides are determined. The observation of fluorescence from dye molecules with concentrations of 10 nmol/l is described. Higher-level integration towards compact, planar, and massively parallel sensors on a chip is discussed.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
10/2004;
