Liquid Waveguide-Based Evanescent Wave Sensor That Uses Two Light Sources with Different Wavelengths

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• 作者：Jong-Min Lim ; John Paul Urbanski ; Jae-Hoon Choi ; Todd Thorsen ; Seung-Man Yang
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：January 15, 2011
• 年：2011
• 卷：83
• 期：2
• 页码：585-590
• 全文大小：212K
• 年卷期：v.83,no.2(January 15, 2011)
• ISSN：1520-6882

文摘

We demonstrate a prototypic optofluidic evanescent wave sensor made of poly(dimethylsiloxane) (PDMS) elastomer in which two light sources with different wavelengths are coupled into an optofluidic liquid-core/liquid-cladding (L²) waveguide. The exponentially decaying evanescent wave interacts with analyte molecules dissolved in the cladding fluids or products formed by in situ reactions at the core鈭抍ladding interface. The analyte molecules exhibit distinctly different light absorbance at the two wavelengths during the light鈭抋nalyte interaction. Therefore, by using the normalized absorbance calculated from the intensity ratio of the two wavelengths instead of the absolute magnitude of either signal, unwanted effects from omnipresent external noise sources can be reduced. In addition, the differential absorption of the two beams by the analyte solutions can be used to enhance the resolution of sample analysis. The evanescent wave sensor based on a liquid waveguide can also be used for real-time monitoring of chemical reactions, because the core and cladding fluids in the L² waveguide are slightly miscible at the core鈭抍ladding interface due to the diffusional mixing.