Abstract
This paper proposes a methane sensor based on localized surface plasmon resonance (LSPR) of a hexagonal periodic gold nanoring array. The effects of structural parameters on the extinction spectrum and refractive index (RI) sensitivity are analyzed to obtain optimal parameters. In particular, the RI sensitivity can reach 550.08 nm/RIU through improvement of the sensor structure, which is an increase of 17.4% over the original value. After coating a methane-sensitive membrane on the inner and outer surfaces of the gold rings, the methane concentration can be accurately measured with a gas sensitivity of −1.02 nm/%. The proposed method is also applicable to quantitative analyses of components concentration and qualitative analyses of gas composition.
Highlights
Surface plasmon polariton (SPP) [1,2,3,4,5] is a surface free-electron oscillation existing at the interface between two materials with a dielectric constant of the opposite sign
The localized surface plasmon resonance (LSPR) behavior [6,7,8,9] is a free-electron oscillation that is usually confined to metal nanostructures
This study study proposed proposed an an LSPR
Summary
Surface plasmon polariton (SPP) [1,2,3,4,5] is a surface free-electron oscillation existing at the interface between two materials with a dielectric constant of the opposite sign. In 2018, Wang et al designed a periodic gold nanoring array for refractive index (RI) measurements with a sensitivity of 544 nm/RIU [17]. Speaking, the coupling strength of hexagonal periodic gold nanorings is larger than that of other sensor structures with much simpler fabrication processes. This provides us with a new means for solving some difficult problem related to the measurement of gas by optical sensing. In contrast to reported gas sensors [21,22,23], the coating process was simpler, and the sensor structure was conducive to an enhancement in the gas sensitivity for rapid concentration measurements
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