Blank Alexandra, Guendelman Gabriel, Linzon Yoav
School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
Chemical Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel.
Sensors (Basel). 2020 May 8;20(9):2675. doi: 10.3390/s20092675.
Optical microfiber tapers provide an advantageous platform for sensing in aqueous and gas environments. We study experimentally the photonic transmission in optical fiber tapers coated with polymethyl methacrylate (PMMA), a polymeric material widely used in optical applications. We demonstrate a durable and simple humidity sensing approach incorporating tapered microfibers attached to silicon (Si) substrate coated with active polymer layer. A model is described for the load stress effect on the birefringence giving rise to interferences in the transmission spectra, strongly dependent on the coating layer thickness, and disappearing following its slow uniform removal. The sensing approach is based on characterization of the interference patterns observed in the transmission spectra of the taper in the NIR range. The device demonstrated persistent detection capability in humid environment and a linear response followed by saturation to calibration analytes. In each analyte of interest, we define principal components and observe unique calibration plot regimes in the principal component space, demonstrating vapor sensing using polymer coated microtapers.
光学微光纤锥为在水性和气体环境中进行传感提供了一个有利的平台。我们通过实验研究了涂覆有聚甲基丙烯酸甲酯（PMMA）的光纤锥中的光子传输，PMMA是一种广泛用于光学应用的聚合物材料。我们展示了一种耐用且简单的湿度传感方法，该方法结合了附着在涂有活性聚合物层的硅（Si）衬底上的锥形微光纤。描述了一个模型，用于说明负载应力对双折射的影响，这种影响会在传输光谱中产生干涉，强烈依赖于涂层厚度，并且在涂层缓慢均匀去除后消失。该传感方法基于对近红外范围内光纤锥传输光谱中观察到的干涉图案的表征。该器件在潮湿环境中表现出持续的检测能力，并且对校准分析物呈现线性响应，随后达到饱和。在每种感兴趣的分析物中，我们定义了主成分，并在主成分空间中观察到独特的校准曲线区域，证明了使用聚合物涂覆的微锥进行蒸汽传感。
