title: Plasmonic nanosensor based on Fano resonance in waveguide-coupled resonators.
abstract: We propose a plasmonic nanosensor based on Fano resonance in the strong-confinement metal-dielectric-metal waveguide side-coupled with a pair of nanoresonators. Due to the coherent interference of the splitting discrete and quasi-continuum modes, the reflection spectrum possesses a sharp asymmetric Fano resonance dip, which is dependent on the cavity-cavity phase and the refractive index change of the dielectric. The physical features contribute to a highly efficient plasmonic sensor for refractive index sensing. The nanosensor yields a sensitivity of ~900 nm/RIU and a figure of merit of ~500, remarkable values compared with those of plasmonic sensors supported by perfect absorbers.
authors.affiliation: State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Lu
authors.forename: Xueming
authors.initials: X
authors.lastname: Liu
authors.forename: Dong
authors.initials: D
authors.lastname: Mao
authors.forename: Guoxi
authors.initials: G
authors.lastname: Wang