Accurate monitoring of concentration changes in saline solution is prerequisite to control and minimize the negative effect of salt in water resources. A highly sensitive refractive index (RI) sensor is fabricated via coating a novel zinc oxide/silver (ZnO/Ag) bi-layer having different ZnO nanostructure shapes as an outer layer on partially unclad silica fiber. When the ZnO layer contact to different saline concentrations, its band-gap is altered and modifies the RI of the ZnO layer. The coupling of the evanescent light with surface plasmon resonance (SPR) wave and absorption of evanescent light by the external medium are responsible for observing wavelength shift and intensity changes in the detected spectrum. For vertically oriented ZnO nanorods sample when IR light is used as a light source, by increasing the saline concentration from 0% to 20%, the wavelength is shifted from 1564.4 nm to 1573.3 nm and the intensity is dropped to 77% of its maximum value. The superior sensitivity obtained for vertically oriented ZnO sample is attributed to the larger surface area, higher average dispersion relation, better crystallinity, larger surface roughness and greater adhesion (interaction) with salt molecules compare to the other samples. The experimentally demonstrated highest intensity and wavelength sensitivity are 36 dB/RIU and 255 nm/RIU respectively.

准确监测盐溶液中浓度的变化是控制和最大程度减少盐分对水资源的负面影响的前提。通过将具有不同ZnO纳米结构形状的新型氧化锌/银（ZnO / Ag）双层涂覆为部分未包覆的二氧化硅纤维上的外层，可以制造出高灵敏度折射率（RI）传感器。当ZnO层接触到不同的盐浓度时，其带隙会改变并改变ZnO层的RI。e逝光与表面等离子体激元共振的耦合（SPR）波和外部介质对e逝光的吸收负责观察波长变化和检测光谱中的强度变化。对于使用红外光作为光源的垂直取向ZnO纳米棒样品，通过将盐水浓度从0％增加到20％，波长从1564.4 nm移到1573.3 nm，强度降低到最大值的77％ 。与其他样品相比，垂直取向的ZnO样品具有更高的灵敏度，这归因于更大的表面积，更高的平均分散度关系，更好的结晶度，更大的表面粗糙度以及与盐分子的更大附着力（相互作用）。实验证明最高强度和波长灵敏度分别为36 dB / RIU和255 nm / RIU。