The ability of detecting harmful chemicals is an important safety requirement for drinking water systems. An apparatus for in-water chemical sensing based on the absorption of evanescent waves generated by a quantum cascade laser array propagating in a silver halide optical fiber immersed into water is demonstrated. We present a theoretical analysis of the sensitivity of the system and experimentally characterize its real-time response and spectroscopic detection for injection of a sample chemical (ethanol) in a tube containing water.
@article{arxiv.1801.06530,
title = {In-water chemical sensing by fiber-optic evanescent waves spectroscopy using mid-infrared quantum cascade lasers},
author = {Paul Chevalier and Marco Piccardo and Guy-Mael de Naurois and Ilan Gabay and Abraham Katzir and Federico Capasso},
journal= {arXiv preprint arXiv:1801.06530},
year = {2018}
}