▎ 摘　　要

Localized surface plasmon resonance (LSPR) optical fiber biosensing is an advanced and powerful label-free technique which gets great attention fig its high sensitivity to refractive index change in surroundings. However, the pursuit of a higher sensitivity is still challenging and should be further investigated. In this paper, based on a monolayer graphene/gold nanoparticles (Gr(m)/Au NPs) three-dimensional (3D) hybrid structure, we fabricated a D-shaped plastic optical fiber (D-POF) LSPR sensor using a facile two-step method. The coupling enhancement of the resonance of this multilayer structure was extremely excited by the surface plasmon property of the stacked Au NPs/Gr(m) layer. We found that the number of plasmonic structure layers was of high importance to the performance of the sensor. Moreover, the optimal electromagnetic field enhancement effect was found in three-layer plasmonic structure. Besides, the n*(Gr(m)/Au NPs)/D-POF sensor exhibited outstanding performance in sensitivity (2160 nm/RRJ), linearity (linear fitting coefficient R-2 = 0.996) and reproducibility. Moreover, the sensor successfully detected the concentration of glucose, achieving a sensitivity of 1317.61 nm/RIU, which suggested a promising prospect for the application in medicine and biotechnology. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement