From localized to propagating surface plasmon resonances in Au nanoparticle-coated optical fiber sensors and its implications in biosensing  

作　　者：PAULO S.S.DOS SANTOS JOÃO P.MENDES JORGE PÉREZ-JUSTE I.PASTORIZA-SANTOS JOSÉM.M.M.DE ALMEIDA LUÍS C.C.COELHO 

机构地区：[1]INESC TEC–Institute of Systems and Computer Engineering,Technology and Science,and Department of Physics,Faculty of Sciences,University of Porto,Rua do Campo Alegre,4169-007 Porto,Portugal [2]Faculty of Engineering,University of Porto,Rua Dr.Roberto Frias,4200-465 Porto,Portugal [3]CINBIO,Universidade de Vigo,Campus Universitario Lagoas,Marcosende,36310 Vigo,Spain [4]SERGAS-UVIGO,Galicia Sur Health Research Institute(IIS Galicia Sur),36312 Vigo,Spain [5]Department of Physics,School of Science and Technology,University of Trás-os-Montes e Alto Douro,5001-801 Vila Real,Portugal

出　　处：《Photonics Research》2024年第10期2166-2177,共12页光子学研究（英文版）

基　　金：Funda??o para a Ciência e a Tecnologia(CEECIND/00471/2017,Grant Agreement 101084383,SFRH/BD/130674/2017,SFRH/BD/146784/2019);Xunta de Galicia(GRC ED431C 2020/09)。

摘　　要：Nanoparticle-based plasmonic optical fiber sensors can exhibit high sensing performance,in terms of refractive index sensitivities(RISs).However,a comprehensive understanding of the factors governing the RIS in this type of sensor remains limited,with existing reports often overlooking the presence of surface plasmon resonance(SPR)phenomena in nanoparticle(NP)assemblies and attributing high RIS to plasmonic coupling or waveguiding effects.Herein,using plasmonic optical fiber sensors based on spherical Au nanoparticles,we investigate the basis of their enhanced RIS,both experimentally and theoretically.The bulk behavior of assembled Au NPs on the optical fiber was investigated using an effective medium approximation(EMA),specifically the gradient effective medium approximation(GEMA).Our findings demonstrate that the Au-coated optical fibers can support the localized surface plasmon resonance(LSPR)as well as SPR in particular scenarios.Interestingly,we found that the nanoparticle sizes and surface coverage dictate which effect takes precedence in determining the RIS of the fiber.Experimental data,in line with numerical simulations,revealed that increasing the Au NP diameter from 20 to 90 nm(15%surface coverage)led to an RIS increase from 135 to 6998 nm/RIU due to a transition from LSPR to SPR behavior.Likewise,increasing the surface coverage of the fiber from 9%to 15%with 90 nm Au nanoparticles resulted in anincrease in RIS from 1297(LSPR)to 6998 nm/RIU(SPR).Hence,we ascribe the exceptional performance of these plasmonic optical fibers primary to SPR effects,as evidenced by the nonlinear RIS behavior.The outstanding RIS of these plasmonic optical fibers was further demonstrated in the detection of thrombin protein,achieving very low limits of detection.These findings support broader applications of high-performance NP-based plasmonic optical fiber sensors in areas such as biomedical diagnostics,environmental monitoring,and chemical analysis.

关 键 词：FIBER surface fibers 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]