title: Highly versatile fiber-based optical Fabry-Pérot gas sensor.
abstract: We develop a versatile, compact, and sensitive fiber-based optical Fabry-Pérot (FP) gas sensor. The sensor probe is composed of a silver layer and a vapor-sensitive polymer layer that are sequentially deposited on the cleaved fiber endface, thus forming an FP cavity. The interference spectrum resulting from the reflected light at the silver-polymer and polymer-air interfaces changes when the polymer is exposed to gas analytes. This structure enables using any polymer regardless of the polymer refractive index (RI), which significantly enhances the sensor versatility. In experiments, we use polyethylene glycol (PEG) 400 (RI=1.465-1.469) and Norland Optical Adhesive (NOA) 81 (RI=1.53-1.56) as the gas sensing polymer and show drastically different sensor response to hexanol, methanol, and acetone. The estimated sensitivity for methanol vapor is 3.5 pm/ppm and 0.1 pm/ppm for PEG 400 and NOA 81, respectively, with a detection limit on the order of 1-10 ppm. Gas sensing for the analytes delivered in both continuous flow mode and pulsed mode is demonstrated.
authors.affiliation: Biological Engineering Department, University of Missouri, 240D Bond Life Sciences Center, 1201 E. Rollins Street, Columbia, Missouri 65211, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Yuze
authors.initials: Y
authors.lastname: Sun
authors.forename: Xudong
authors.initials: X
authors.lastname: Fan
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D017022:Flow Injection Analysis / Q000295:instrumentation*; D005740:Gases / Q000032:analysis*; D007368:Interferometry / Q000941:ethics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers
chemical_list: D005740:Gases