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Low‐Index‐Contrast Dielectric Lattices on Metal for Refractometric Sensing
Author(s) -
Dong Jinwu,
Chen Shuai,
Huang Guangfei,
Wu Qiong,
Huang Xiaocong,
Wang Lingfei,
Zhang Yuan,
Ao Xianyu,
He Sailing
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202000877
Subject(s) - materials science , nanopillar , refractive index , dielectric , plasmon , surface plasmon resonance , optics , electric field , resonance (particle physics) , optoelectronics , lattice (music) , nanotechnology , nanostructure , physics , particle physics , quantum mechanics , nanoparticle , acoustics
This article reports refractometric sensing using two optical resonances of different types supported by TiO 2 nanopillar arrays on a gold film, which can be exposed to aqueous or organic environments. One lattice resonance, with enhanced electric fields extending into the surrounding environment, can maintain a quality factor Q > 200 when the bulk refractive index of the surrounding environment varies in a large range from 1.33 to 1.58. This lattice resonance exhibits not only sharp transitions of reflected light intensity but also rapid phase changes. The other resonance is of plasmonic nature with electric fields localized on the metal surface. Small changes in the bulk refractive index or the adsorbate layer (thickness and index) can be detected, with sensitivity comparable to that of plasmonic counterparts. The present hybrid metal–dielectric platform is promising for applications requiring dielectric instead of metallic sensing surfaces.