Humidity Sensors Using Nanofilms Deposited on Hollow Core Fibers

by Ignacio R. Matias et al. SPIE Newsroom, accessed 7 Sep 2006 Hollow core fibers (HCFs), transmit light through a central air hole. Recent developments make HCF technology suitable for detecting moisture, and we are using it to develop relative humidity sensors. HCFs are especially attractive because one can deposit on them nanofilms that make it possible to modulate the so-called evanescent -- that is, highly localized -- electromagnetic field as a function of the external medium. In our work, we coat the fibers with a humidity-sensitive nanofilm whose thickness is the same order of magnitude as that of the evanescent field penetration length. Read more