Precise control of evanescent scattering by self-assembled ferromagnetic particles for optical sensing with tunable sensitivity

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Original languageEnglish
Article number343101
Pages (from-to)5889-5892
Number of pages4
Journal / PublicationOptics Letters
Issue number23
Online published30 Nov 2018
Publication statusPublished - 1 Dec 2018


We propose an optical sensing platform that uses evanescent scattering through precise manipulation of self-assembled ferromagnetic particle columns. The movement of column tips can be dynamically controlled down to a submicron range by an external actuation, namely, magnetic field, for interacting with evanescent wave propagation along an optical waveguide that causes a change in its output intensity for optical sensing. To demonstrate the idea, an AC current sensor with only a 5 mm interaction length is proposed and realized. Furthermore, its sensitivity is tunable within 9–20 dB/A by varying a DC-biased signal. The platform shows favorable signal reversibility, stability, broadband operation, and real-time response.