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LSPR spectral properties of Au nano-ring arrays and single Au nanoparticles

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LSPR spectral properties of Au nano-ring arrays and single Au nanoparticles

    LSPR spectral properties of Au nano-ring

    arrays and single Au nanoparticles 3卷第1

    20102

    

    ChineseJournal

    国光学与应用光学

    ofOpticsandAppliedOptics

    V01.3No.1

    Feb.20lO

    文章编号16742915(2010)01007504

    LSPRspectralpropertiesofAunano?ring

    arraysandsingleAunanoparticles

    MAJunxian,TANRuihu,FANGYu,ZHENGDawei,LUOXiangang

    (AdvancedTechnologyResearchCenter,ShenzhenUniversity,Shenzhen518060,China) Abstract:Inthispaper,wesimulateLocalizedSurfacePlasmonResonance(LSPR)absorptionofperiodicAu

    nan()

    ringarraysandsingleAunanopartielesusingtheFiniteDifferenceTimeDomain(FDTD)method.We

    chooseinputplanewavesofdifferentwavelengthsanddiscusstherelationbetweentheabsorptionpeakofthe

    Auarrayandthevariableexternaldielectricconstants.Itisfoundthatthesensitivityofthesesensorsbasedon

    LSPRisimprovedcomparedtothecommonsensorsandtheenhancementiscausedbytheperiodicalstructure.

    WealsoinvestigatethespectrumcharacteristicofasingleAunanoparticleanddiscusstherela

tionbetweenthe

    absorptionpeakandthesizeofthenanopartiele. Keywords:LSPR;absorptionspectrum;3DFDTD;nanopartieles LocalizedSurfacePlasmonResonanee(JlJSPR) accountsforintensedispersionandabsorptionwhen metalnanoparticlesareincitedbyvisiblelightor infraredray.Itisaphysicalphenomenoncausedby theresonantcouplingbetweentheincidentelectro

    magneticfieldandtheconductionelectronsinthe meta1.Whentheexterna1dielectricconstantisa constant,metalnanoparticleshaveanobvious absorptionataparticularwavelengthoftheincident lightandthesurfaceplasmonwaveislocalizedby thesurroundingthemetalnanoparticles.Weanalyze theLSPRspectralpropertiestostudytheI~PR phenomenonbasedonthemetalnanostructure. Whenwechangethedielectricconstant,theabsorp

    tionpeakwillshift.Byusingthisopticalcharacter

    istic,LSPRcouldbeusedinmaterialsensorsto achievehighlysensitivity.Inthispaper,wefocus ontheshiftsofLSPRabsorptionpeakwhenthedie

    leetrieconstantandthesizeofmetalnanopartieles arechanged.

    2Numericalsimulationandparameter

    setting

    WechoosetheLorentzDrudemodeItoanalysethe

    LSPRphenomenonofthemetaldispersionmaterial, andtheLSPRabsorptionpeakiscalculatedfrom Maxwellequationsusinga3DFiniteDifferenceTime Domain(FDTD)simulationmethod.

TheparametersofAunanoringarraysimula

    tionare:TMplanewave;wavelength(12202600

    Recei~reddate:200910-11;Reviseddate:200912-13.

    Foundationitems:supportedbytheMajorStateBasicResearchandDevelopmentProgram(9

    73Program)(2006CB302900);

    NationalNatureScienceFoundationofChina(60772026). 76中国光学与应用光学第3

    nm);3×3Aunanoringarrayplacedontheg1ass

    su1)strate;theheightofAuringis40nmwitha thicknessof35nmandtheperiodis400nm.The parametersofasingleAnnanoparticlesimulation are:TMplanewave;wavelength(1080

    1400nll1);asingleAunanopartieleplaced0nthe glasssubstrate;heightis40nm

    ,andtheradiusis

    stto150,175,200,225,250,2750r300nm. Theabsorbingbounda~conditionisch()sentobea perfectlymatchedlayer(PML)absorbingboundary conditionforalIthesimulati0ns

    a)

    25

    3ResultsandConclusj0ns

    Fig.1showsthestructureoftheAunan0.ringsarray andltsenergydistributionatA=1440nln.withthe greenpansintherighthandchartdenotinghighe/l- ergy.FromFig.1wecarlseethattheenergyiseen- tralizedontheedgesofparticles,whichmeansthe energyabsorptionoftheincidentlightisconeentrat. edintheexterioroftheAunan0rings.

    O

050——0

    

    I050--0.525O00005251050

    ..

    {b)

    1StructureoftheAurlan.ringairaYanditsenergydistributi(JnatA:1440nm

    Inordertostudytherelationshipbetweenthe dielectricconstantandtheabsorptionpeak ,weset

    n1,1.3,1.4respectively,andtheresuItsare showninFig.2.

    Wecanseetheabsorptjonpeak

    locatesat1500,

    1800,1900nm,respectivelv.

    andthepositionofabsorptionpeakisred

    shifted

    Fig?2Absorpti.nspeerFunofAunano- rings

    whenthedie1eetricc0nstantisincreasing.Thepeak isshiftedabout100nmwhilethedie1ectricconstant increasesby0.1.

    Thenweundertookacomparativeexperimentof Fig-3ComparisODofasingleAunanoparti(1eand3×

    3Auarray.

    asingleAunanoparticleanda3×3Auarravto

    0ucB1(1c?c

    000?D0Lu0

    dx

    Y

    0

    DFTE

    Fig,4siru([1jre.fsi"g1eA unan.particleanditsenergydis,一bufi.n

    at:138Onm

    b'romtheleftchaninFig .5,wecanseethat

    theab.rpt."peakisred

    shiftedwhentheradiusof Aunanpartileisincreasing. Theghtpicture

    sh'wsalnearrelationshipbetweenthera(ij

    usand

    fhe0cati0n0fabs0I"ptionpeak ,andthewavelength

    '?absorP?onpeakincreaseswhenther adiusjs

    nc'easng?Iherearetwoint]e~tionpoix1t

    sbetween

    Fig?5bsorpthIJ1spectnlm()f an

    alfiel~andpeakposltion. ?83

    10s 2.48×

    2.i2×IO

    1.77×108

    1.42×108

    106~1On

7.08×107

    3.54X107

    O.OO

    150nmand175nmandbet

    ween275nmand300

    nm,reSpectively?Furthermore ,wecanseehe

    Jb.tw.e"150nmand175nrnis1 arger,which

    meanstheAunanopartielewh()seradi usjssma11er

    than175nmismoresensiti

    veamundtheabs.rDti.n

    1

    I

    E

    jJ

    ,

    1

    Radius/un1

    A"ntpaltice.fdjffIntsjzesa

    ndtf1eT?lationshipbetweelltheradi usoftheAunan.p

    })lJ.NjLIjcz

    78中国光学与应用光学第3

    3Conclusions

    Fromoursimulationexperiments,wecanconclude

    thattheabsorptionpeakwillshiftwhenthedielectric

    constantischanged,andtheintensityofabsorption

    isrelatedtothedimensionofthesingleparticle.The

periodicnanostructurecanlocalizeandenhancethe

    electromagneticfieldselective1)r,therefore,its

    Referenees:

    sensitivitycanbeimprovedbyincreasingthenumber

    ofperiodicparticles.Furthermore,thereisalinear

    relationshipbetweentheradiusandtheabsorption

    peak,andthetwoinflectionpoints.Theresult

    meansthatAunaooparticlesaremoresensitiveto

    thechangeofwavelengthwhentheradiusisbelowa

    certainvalue,SOwecancontrolthepositionofthe

    LSPRabsorptionpeakbydesigningdifferentsizesof

    meta1nanopartic]es.

    [1]TOMINAGAJ,TSAIDP.OpticalNanotehcnologies

    theManipulationofSurfaceandLocalPlasmons[M].Heidelberg, Springer,2002:512-515.

    [2]KIMS,JUNGJM,CHOIDG,eta1..PatternedarraysofAuringsf0rlocalizedsurfaceplasmonresonance[J].Langmuir,

    2006,22(17):71097112.

    [3]STUARTDA,HAESAJ,YONZONCR,eta1..Biologicalapplicationsoflocalizedsurfaceplasmonicphenomenae[J].

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    SAYEDMA.Someinterestingpropertiesofmetalsconfinedintimeandnanometerspaceofdifferentshapes[J].Acc.

    Chem.Res.,2001,34(4):257264.

    [5]HUTFERE,FENDLERJH.Exploitationoflocalizedsurfaceplasmonresonance[J].Adv.Mater.,2004,16(19):1685

    1706.

    [6]LINKS,EL

    SAYEDMA.Spectralpropertiesandrelaxationdynamicsofsurfac,eplasmonelectronicosci

llationsingold

    andsilvernanodotsandnanorods[J]..,.Pbys.Chem.B,1999,103(40):841O-8426.

    Authorbiography:MaJunxian(1961

    ),male,professorofAdvancedTechnologyResearchCenterofShenzhenUniversity, hisresearchinterestsal'esubwavelengthopticaldevicesandbroadbandopticalnetwork,etc. Email:majx@SZH.edu.cn

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