Humidity evanescent hollow core fiber sensor

We have tested the viability of fabrication of evanescent sensors using tapered hollow-core fiber (HCF). Two different methods were used to build these sensors: the first one, using a hydrogel as the sensing coating; the second one, by means of the electrostatic self-assembly method for the deposition of thin films on the surface of the hollow-core fiber. In both cases, in order to demonstrate the phenomenon, humidity sensors were fabricated.