An abrupt change in optical transmission characteristic of a graphene oxide (GO) coated optical planar waveguide was observed. This observation was based on the peculiar characteristics of the graphene oxide film, namely its high transverse-electric polarized light propagation loss, highly selective permeability of water, and change in optical propagation characteristic in the presence of water. The as-fabricated GO-coated optical waveguide showed a large polarization dependent loss of ~32 dB in the C-band optical fiber communication window (1550 nm). The response of the proposed sensor was first tested by using water. When a drop of water was applied onto the GO coating, the large polarization dependent loss was fully suppressed almost instantaneously. This effect was reversible as the polarization dependent loss was restored after complete water evaporation from the GO coating. All-optical measurement of water content in alcohol was then demonstrated by using the GO-coated optical waveguide. By analyzing the drying profile of the water-alcohol mixture, water content in the range of 0.2 volume % – 100 volume % could be measured. These measurements were carried out by using solution volume of 1.0 μL only. The all-optical sensing nature of the proposed sensor has potential applications in in-situ monitoring of water content in alcohol.

中文翻译：

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氧化石墨烯功能化光学平面波导，用于酒精中的水含量测量

观察到涂覆有氧化石墨烯（GO）的光学平面波导的光传输特性突然变化。该观察是基于氧化石墨烯膜的独特特性，即其高的横向电偏振光传播损耗，水的高选择性渗透性以及在水存在下光学传播特性的变化。刚制成的GO涂层光波导在C波段光纤通信窗口（1550 nm）中显示了约32 dB的大偏振相关损耗。建议的传感器的响应首先通过用水进行测试。当在GO涂层上滴一滴水时，几乎瞬间就可以完全抑制大的偏振相关损耗。这种作用是可逆的，因为从GO涂层中完全蒸发掉水后，偏振相关的损耗得以恢复。然后通过使用GO涂层的光波导演示了酒精中水含量的全光学测量。通过分析水-醇混合物的干燥曲线，可以测量0.2体积％至100体积％范围内的水含量。仅使用1.0μL的溶液体积进行这些测量。所提出的传感器的全光传感特性在酒精中水含量的原位监测中具有潜在的应用。可以测量2体积％– 100体积％。仅使用1.0μL的溶液体积进行这些测量。所提出的传感器的全光传感特性在酒精中水含量的原位监测中具有潜在的应用。可以测量2体积％– 100体积％。仅使用1.0μL的溶液体积进行这些测量。所提出的传感器的全光传感特性在酒精中水含量的原位监测中具有潜在的应用。