Fiber optic Fabry-Perot sensor for surface tension analysis

We demonstrate a new technique for analyzing surface tension of liquids. This is done upon examining the interference signals reflected from a remnant drop pending at the cleaved end of a single mode optical fiber. The resulting interference patterns are fitted to a multimirror Fabry-Perot model yielding information of the drop size. We show that the wetting process of the fiber plays an important role in drop formation; in particular, the drop size can be correlated to the surface tension of the liquid sample. The proposed configuration may render useful for liquids analysis using small sample volume.