A novel technique was designed to measure the meniscus height (MH) of liquids on a standard single mode fiber (SMF) using fiber optics. Once the MH is known, the contact angle could be calculated, and the surface tension of liquids can be determined. In this paper, the MH is measured using a cleaved and side polished optical fiber attached to a SMF with a known separation distance between their fiber tips. When the liquid reaches the SMF, the liquid meniscus rises on the vertical wall of the SMF, which also causes a variation in mass (measured by a μg scale). At this point, the liquid moves upwards until the liquid meniscus touches the side polished fiber, which registers a variation of the reflected optical power. The MH seems to increase as the surface tension decreases, and the variation of the mass measured by the scale increase with the increase of the surface tension. This sensor was also used to measure the interfacial surface tension of the air-liquid and liquid-liquid interface since the contact angle could be measured. In addition, the small dimension of the sensor is adequate for applications where using small amounts of liquid is critical, i.e., biomedical applications.

中文翻译：

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利用光纤测量液体弯月面高度的新技术


设计了一种新技术，利用光纤测量标准单模光纤 (SMF) 上液体的弯液面高度 (MH)。一旦已知 MH，就可以计算接触角，并可以确定液体的表面张力。在本文中，使用连接到 SMF 的劈开且侧面抛光的光纤来测量 MH，光纤尖端之间的间隔距离已知。当液体到达 SMF 时，液体弯月面在 SMF 的垂直壁上上升，这也会引起质量的变化（以 μg 尺度测量）。此时，液体向上移动，直到液体弯月面接触侧面抛光的光纤，从而记录反射光功率的变化。 MH似乎随着表面张力的降低而增加，并且天平测量的质量的变化随着表面张力的增加而增加。由于可以测量接触角，该传感器还用于测量气-液和液-液界面的界面张力。此外，传感器的小尺寸足以满足需要使用少量液体的应用，即生物医学应用。