简介：

简介：

简介：Higher-bandself-trappingandoscillation(rotation)ofnonlinearquadruplebeamsintwo-dimensional(2D)squarephotoniclatticesarenumericallydemonstrated.Underappropriateconditionsofnonlinearity,aquadruple-likebeamcanself-trapintolocalizedmodesthatresideinthesecondBraggreflectiongapthroughsingle-siteexcitation.Bychangingtheinitialorientationoftheincidentquadruplebeamrelatedtothelattices,periodicoscillationsofthelocalizedquadruplemodemaybeobtained.Thelocalizedquadruplestatebecomesarotatingdoublychargedopticalvortex(DCV)duringrotationandshouldundergocharge-flippingwhentherotatingdirectionisreversed.

简介：Anewscreen-spotimagingmethodbasedonopticalmeasurementisproposed,whichisapplicabletotheclose-rangemeasurementofaircraft'sthree-dimensional(3D)attitudeparameters.Lasertrackerisusedtofinishtheglobalcalibrationsofthehigh-speedcamerasandthefixedscreensontestsite,aswellastoestablishmedia-coordinate-framesamongvariouscoordinatesystems.Thelasercooperationobjectmountedontheaircraftsurfaceprojectslaserbeamsonthescreensandthehigh-speedcamerassyn-chronouslyrecordthelight-spots'positionchangingwithaircraftattitude.Therecordedimagesequencesareusedtocomputetheaircraftattitudeparameters.Basedonthematrixanalysis,theerrorsourcesofthemeasurementaccuracyareanalyzed,andthemaximumrelativeerrorofthismathematicalmodelisestimated.Theexperimentalresultshowsthatthismethodeffectivelymakesthechangeofaircraftpositiondistinguishable,andtheerrorofthismethodisnomorethan3′whiletherotationanglesofthreeaxesarewithinacertainrange.

简介：Anovelno-guidelightpentype3D-coordinatemeasurementsystemwiththreesetsofpositionsensitivedevices(PSDs)torealizeintersectionconvergeinagingisintroduced.Itiscalledasthelightpentypemeasurementsystem,becausethemeasuringheadisshapedasapenwithseverallightsourcesonit.Thestructuredesign,measurementprincipleandexperimentalresultsarepresented.Thetheoreticalanalysisandexperimentalresultsprovethatthissystemhasadvancedfeaturesofsimplestructure,highautomation,andhighaccuracy,andcanbeusedinthemeasurementfieldsofmechanicalmanufacture,robot,auto,aviationandmedicineeffectively.

简介：Measurementoflightdistributioninbiologicaltissuecontributestoselectingstrategyandoptimizingdoseforbiomedicalapplication.Inthisletter,aphotoacousticmethodcombinedwithMonteCarlosimulationwasusedtoestimatethethree-dimensionallightdistributioninbiologicaltissue.Thelightdistributionwasproducedbyacylindricaldiffuserwhichinterposedintotissues.Thelightprofilesobtainedbythemethodwerecomparedtothosedetectedbyphotodiodes.Theexperimentalresultsdemonstratethefeasibilityofthismethod.Theapproachcanplayasignificantroleforphoto-dosimetryinbiomedicalphototherapy.

简介：与传统宽波段成像系统相比,多光谱成像系统在性能表征、测试方法等方面有较大不同,而相关研究较为欠缺。因此,需要重点研究多光谱成像系统的综合性能评估方法。解决了目标光谱反射率等效控制、宽波段光谱维度的带内细分和标准靶标辐亮度调节等关键技术,设计了基于AOTF的多光谱成像系统二维鉴别率阈值测试平台及测试方法。在理论分析基础上,实际搭建了基于AOTF的可见光多光谱成像系统,叙述了系统标定方法和测试步骤,并基于所述方法在实验室条件下完成了系统空间分辨率、目标光谱反射率与对比度阈值的三维曲面测试实验。测试结果标明,所提出的方法可较好地反映不同谱段响应特性的差异,实现对多光谱成像系统的性能表征。基于该方法,可综合评估系统光谱分辨率、空间分辨率、灵敏度、对比度等性能指标,从而为多光谱成像系统性能的定量表征提供技术支持。

简介：WedesignaD-shapedfiberopticbiosensorbasedonthesurfaceplasmonresonance(SPR)ofametal-graphenelayerandsimulatethisSPRusingthefiniteelementmethod.Usingametal-graphenelayerasthesensingmaterial,surfaceplasmaresonanceissimulatedastherefractiveindexoftheexternalenvironmentrangesfrom1.33to1.36.Simulationresultsshowthatametal-graphenelayerattachedtotheD-shapedopticalfibercorecancouplewithlightunderaspecificpolarizationstateandexcitestrongplasmaoscillationsonthelayersurface.Calculatedtransmissioncoefficientsshowthattheresonancewavelengthobviouslymovestowardlongerwavelengthsastherefractiveindexofthetestmediumincreases,andasensitivityof5400nm/RIUisobtained.Becauseofitslargesurfacevolumeratioandgoodbiocompatibility,graphenemaybeutilizedinmanyapplicationsinthefieldofbiosensing.

简介：Usingamicrowavegenerator,chlorinedilutedbyheliumwasdissociatedtochlorineatomsthatsubse-quentlyreactedwithhydrogenazidetoproducetheexcitedstatesofNCl(a1△).Meanwhile,moleculariodinewithcarriergasofheliumreactedwithatomicchlorinetoproduceatomiciodinewhichthenwaspumpedtoexcitedstateofI(2P1/2)byanenergytransferreactionfromNCl(a1△).Inthispaper,thechangesofNCl(a1△)andNCl(bi∑)emissionintensityispresentedwhenI2/HeisintroducedintothestreamofCl/Cl2/He/HN3/NCl(a1△)/NCl(b1∑).ThedependencesofatomiciodineI(2P1/2)onflowratesofgaseswerealsoinvestigated.TheoptimumparametersforI(2P1/2)productionaregiven.

简介：Nitridatedβ-Ga_2O_3(100)substratewasinvestigatedasthesubstrateforGaNepitaxialgrowth.Theeffectsofnitridationtemperatureandsurfaceroughnessofβ-Ga_2O_3wafersontheformationofGaNwerestudied.Itwasfoundthatthemostoptimizednitridationtemperaturewas900°C,andhexagonalGaNwithpreferredorientationwasproducedonthewell-polishedwafer.Thenitridationmechanismwasalsodiscussed.

简介：FourkindsofY2O3stabilizedZrO2(YSZ)thinfilmswithdifferentY2O3contents(from0to12mol%)aredepositedonBK7glasssubstratesbyelectron-beamevaporationmethod.TheeffectsofdifferentY2O3dopantcontentsonresidualstress,structure,andopticalpropertiesofZrO2thinfilmsareinvestigated.TheresultsshowthatresidualstressinYSZthinfilmsvariesfromtensiletocompressivewiththeincreaseofY2O3molarcontent.TheadditionofY2O3isbeneficialtothecrystallizationofYSZthinfilmandtransformationfromamorphoustohightemperaturephase,andtherefractiveindexdecreaseswiththeincreaseofY2O3molarcontent.Moreover,thevariationsofresidualstressandtheshiftsofrefractiveindexcorrespondtotheevolutionofstructuresinducedbytheadditionofY2O3.

简介：WhenfemtosecondlaserpulsesinterferewithchirpedfemtosecondlaserpulsesinAs2S3fiber,achirpedfibergratingisformed.Ananalyticalexpressionisgiventodescribethechirpedgrating,anditsBraggreflectivityiscalculated.BecauseofthehighphotosensitiveeffectofAs2S3material,thechirpedfibergratinghasawideBraggreflectivespectrumandhighreflectivitybychoosingproperparameters.Thisindicatesthatthechirpedfibergratingcanbeusedasastretcherinthefemtosecondchirpedpulseamplification(CPA)system.

简介：TheCa_2SiO_4:Dy~(3+)phosphorwassynthesizedbythehightemperaturesolid-statereactionmethodinair.TheemissionspectrumofCa_2SiO_4:Dy~(3+)phosphorshowsseveralbandsat486,575,and665nmunderthe365-nmexcitation.TheeffectsofLi~+,Na~+,andK~+ontheemissionspectrumofCa_2SiO_4:Dy~(3+)phosphorwerestudied,TheresultsshowthattheemissionspectrumintensityisgreatlyinfluencedbyLi~+,Na~+,andK~+.Thechargecompensationconcentrationcorrespondingtothemaximumemissionintensityisdifferentwithdifferentchargecompensations.

简介：Aperiodicallypoledlithiumniobate(PPLN)opticalparametricgenerator(OPG)pumpedbyalaserdiode(LD)-pumpedQ-switchedTm,Ho:GdVO_4laseroperatedat2.048μmwithpumppulseof25nsandrepetitionrateof10kHzisreported.Acontinuoustunablemiddle-infrared(mid-IR)spectrumof3.88-4.34μmisobtainedbychangingthecrystaltemperaturefrom50to124°C.Whentheincidentpumppoweris3W,thetotalOPGoutputpoweris95mW,correspondingtoopticalconversionefficiencyof3.2%.

简介：AseriesofAlx-(Alq3)1-xgranularfilmsispreparedonSiwaferwithnativeoxidelayerusingco-evaporationtechnique.Largelateralphotovoltaiceffect(LPE)isobserved,withanoptimalLPVsensitivityof75mV/mminx=0.35sample.ThedependenceofLPEontemperatureandAlcompositionisinvestigated,andthepossiblemechanismisdiscussed.

简介：转镜相机像面设计中，基于传统代替圆理论的设计存在原理性误差，而通过综合考虑几种代替圆理论衍生出来的最佳设计理论会出现圆心不重合、转镜中心点偏离坐标中心等问题，对加工和装配的要求高。在数字像面设计中，把转镜旋转中心点设为坐标中心，推导出每个传感器成像像面坐标和像面边缘离焦量方程，从模拟结果可以看出，转镜扫描时形成了Pascal蜗线，且每个像面又单独为一条直线，符合高速转镜原理和本文计算理论的结论。可为像面定位、工作角、倾斜角选取提供依据。

简介：Theeffectofλ/2SiO2overcoatonthelaserdamagecharacteristicsofHfO2/SiO2high-reflector(HR)coatingsisinvestigatedwith1-on-1andN-on-1laserdamagetestmethods.Thelaserdamagesurfaceof1-on-1isanalyzedbyastepanalyzer.ThesurfacemorphologiesshowthatlaserdamagemakesthecoatingdamagedareaprotrudentandroughforHRcoatingwithoutλ/2silicaovercoat,butconcaveandsmoothforHRcoatingwithλ/2silicaovercoat.Theresultof10-on-1multi-pulseirradiationonthesamepointofthecoatingshowsthatthereisanenergydensitystageonthedamagecurve.Ifthelaserenergydensityiswithintherangeofthestage,HfO2/SiO2HRcoatingswithλ/2silicaovercoatwillnotbedamagedmorethan2timesformulti-shots,andthesurfacedamagesareveryslightsothatthereisnoimpactonthecoatingperformance.Anotherinterestingresultisthattheenergydensitystageextendsfromthedamagethresholdtothepointofabout3timesofthreshold,whichissimilartotheeffectofthelaserconditiononcoating.

简介：Enhanced2.7μmemissionisobtainedinEr3+/Tm3+andEr3+/Ho3+codopedZBYAglasses.Absorptionandemissionspectraaretestedtocharacterizethe2.7μmemissionpropertiesofEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesandareasonableenergytransfermechanismof2.7μmemissionbetweenEr3+andTm3+Ho3+)ionisproposed.CodopingofTm3+orHo3+significantlyreducesthelifetimeoftheEr3+:4I13/2levelduetotheenergytransferofEr3+:4I13/2→Tm3+:3F4orEr3+:4I13/2→Ho3+:5I7.Thus,the2.7μmemissionisstrengthenedandthe1.5μmemissionisdecreasedaccordinglyespeciallyintheEr3+/Tm3+sample.TheupconversioneffectsbetweentheEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesaredifferentattributetothedifferentenergytransferefficiencies.Bothofthetwocodopedsamplespossessnearlyequallargeemissioncrosssection(16.6×10-21cm-2)around2.7μm.TheresultsindicatethatthisEr3+/Tm3+orEr3+/Ho3+dopedZBYAglasshaspotentialapplicationsin2.7μmlaser.

简介：MonovalentionsLi+,Na+,andK+,aschargecompensators,areintroducedintoCaYAl3O7:M(M=Eu3+,Ce3+)inthisletter.TheircrystalphasesandphotoluminescencepropertiesofdifferentalkalimetalionsdopedinCaYAl3O7areinvestigated.Inaddition,theinfluenceofchargecompensationionLi+whichhasamoreobviousroleinimprovingluminescenceintensityonCaYAl3O7:Eu3+phosphorisintentionallydiscussedindetailandapossiblemechanismofchargecompensationisgiven.Theenhancementofredemissioncenteredat618nmbelongingtoEu3+isachievedbyaddingalkalimetalionLi+under393-nmexcitation.

简介：Thenonlinearswitchingcharacteristicsoffusedfiberdirectionalcouplerswerestudiedexperimentally.Byusingfemtosecondlaserpulseswithpulsewidthof100fsandwavelengthofabout1550nmfromasystemofTi:sapphirelaserandopticalparametricamplifier(OPA),thenonlinearswitchingpropertiesofanullcoupleranda100%couplerweremeasured.Theexperimentalresultswerecoincidentwiththesimulationsbasedonnonlinearpropagationequationsinfiberbyusingsuper-modetheory.Nonlinearlossinfiberwasalsomeasuredtogettheinjectedpoweratthecoupler.Afterdeductingthenonlinearlossandinputefficiency,thenonlinearswitchingcriticalpeakpowersfora100%andanullfusedcouplerswerecalculatedtobe9410and9440W,respectively.ThenonlinearlossparameterPNinanexpressionofαNL=αP/PNwasobtainedtobePN=0.23W.