title: Significant retrieval of lost evanescent power by tuning modes close-to-cutoff with a gel-coated taper.
abstract: We report a fiber-optic evanescent-wave (EW) sensor capable of dramatically increasing the power collection level by capturing the EW power that is normally lost. The key element is a taper with a thin overlay that is completely separated from the sample by an arbitrary distance and thus operates remotely within the instrumentation system. A two-stage tuning of the close-to-cutoff modes occurring within this element is proposed to interpret the observed phenomenon.
authors.affiliation: College of Optical and Electronic Technology, China Jiliang University, Xueyuan St. Xiasha Higher Education Zone, Hangzhou 310018, China.
authors.forename: Huacai
authors.initials: H
authors.lastname: Chen
authors.forename: Jianjun
authors.initials: J
authors.lastname: Ma
authors.forename: Jiahua
authors.initials: J
authors.lastname: Chen
authors.forename: Wojtek J
authors.initials: WJ
authors.lastname: Bock