简介:Weinvestigatethediffractionoftheguidedmodesofadielectricslabwaveguideonasimpleintegratedstructureconsistingofasingledielectricridgeonthesurfaceofthewaveguide.Numericalsimulationsbasedonaperiodicrigorouscoupled-waveanalysisdemonstratetheexistenceofsharpresonantfeaturesandboundstatesinthecontinuum(BICs)inthereflectanceandtransmittancespectraoccurringattheobliqueincidenceofatransverseelectric(TE)-polarizedguidedmodeontheridge.Usingtheeffectiveindexmethod,weexplaintheresonancesbytheexcitationofcross-polarizedmodesoftheridge.FormationoftheBICsareconfirmedusingatheoreticalmodelbasedoncoupled-wavetheory.ThemodelsuggeststhattheBICsoccurduetothecouplingofquasi-TEandquasi-transverse-magneticmodesofthestructure.SimpleanalyticalexpressionsfortheangleofincidenceandtheridgewidthpredictingthelocationoftheBICsareobtained.Theexistenceofhigh-QresonancesandBICsenablesusingtheconsideredintegratedstructureforsensing,transformationofopticalsignals,andenhancingnonlinearlight–matterinteractions.DuetotheLorentzianlineshapeoftheresonancesneartheBICs,thestructureisalsopromisingforfilteringapplications.
简介:在Zeeman下面的联合格子系统回答的纺纱轨道提供一个理想的平台认识到异国情调的配对的状态。著名例子从拓扑的superfluid/superconducting(tSC)状态,它在体积被豁开但是在边金属性,到Fulde-Ferrell(FF)状态(与一个一致振幅有一个调制阶段的顺序参数)并且Larkin-Ovchinnikov(LO)状态(有一个空间地变化的顺序参数振幅)。这里,我们证明有Chern的拓扑的FF状态数(C=-1)(tFF1)和拓扑的LO与C=2说(tLO2)能在Rashba纺纱轨道被稳定面对在里面飞机和out-of-planeZeeman地联合了格子系统。除不同类的tSC状态以外,面对一块弱在里面飞机Zeeman地,二个拓扑的英国计算机学会阶段可以远离一半充满和C=与C=-1(tBCS1)出现2(半充满附近的tBCS2)。我们为tFF1和tLO1,2状态为FF和LO状态,在不同类的tSC状态之中的拓扑的进化,和不同重要Chern数字显示出象顺序参数的不同空间侧面那样的吸引人的效果,它对格子系统古怪。为各种各样的拓扑的阶段的全球阶段图为充满一半、做的盒子被论述。边状态以及状态系列的本地密度在2D脱衣为tSC状态被计算。
简介:Therealizationofanefficientopticalsensorbasedonaphotoniccrystalmetasurfacesupportingboundstatesinthecontinuumisreported.Liquidswithdifferentrefractiveindices,rangingfrom1.4000to1.4480,areinfiltratedinamicrofluidicchamberbondedtothesensingdielectricmetasurface.Abulkliquidsensitivityof178nm/RIUisachieved,whileaQ-factorofabout2000givesasensorfigureofmeritupto445inairatbothvisibleandinfraredexcitations.Furthermore,thedetectionofultralow-molecular-weight(186Da)moleculesisdemon-stratedwitharecordresonanceshiftof6nmperlessthanaInmthicksinglemolecularlayer.Thesystemexploitsanormal-to-the-surfaceopticallaunchingscheme,withexcellentinterrogationstabilityanddemonstratesalignment-freeperformances,overcomingthelimitsofstandardphotoniccrystalsandplasmonicresonantconfigurations.