简介:Thepolarizationevolutionofvectorbeams(VBs)generatedbyq-platesisinvestigatedtheoreticallyandexperimentally.AnanalyticalmodelisdevelopedfortheVBcreatedbyageneralquarter-waveq-platebasedonvectordiffractiontheory.ItisfoundthatthepolarizationdistributionofVBsvarieswithpositionandthevalueq.Inparticular,fortheincidenceofcircularpolarization,theexitvectorvortexbeamhaspolarizationstatesthatcoverthewholesurfaceofthePoincarésphere,therebyconstitutingafullPoincarébeam.Fortheincidenceoflinearpolarization,theVBisnotcylindricalbutspecularlysymmetric,andexhibitsanazimuthalspinsplitting.Theseresultsareinsharpcontrastwiththosederivedbythecommonlyusedmodel,i.e.,regardingtheincidentlightasaplanewave.Byimplementingq-plateswithdielectricmetasurfaces,furtherexperimentsvalidatethetheoreticalresults.
简介:Anefficientmethodtomountacoupledsilicamicrosphereandtaperedfibersystemisproposedanddemonstratedexperimentally.Forthepurposeofoptomechanicalstudies,high-quality-factoroptical(Q_o~10~8)andmechanicalmodes(Q_m~0.87×10~4)aremaintainedafterthemountingprocess.Forthemountedmicrosphere,thecouplingsystemismorestableandcompactand,thus,isbeneficialforfuturestudiesandapplicationsbasedonoptomechanicalinteractions.Especially,thepackagedoptomechanicalsystem,whichistestedinavacuumchamber,pavesthewaytowardquantumoptomechanicsresearchincryostat.
简介:WithMoS2assaturableabsorber,passiveQ-switchingandQ-switchedmode-lockingoperationsofaTm-dopedcalciumlithiumniobiumgalliumgarnet(Tm:CLNGG)laserwereexperimentallydemonstrated.TheQ-switchedlaseremittedamaximumaverageoutputpowerof62mWandhighestpulseenergyof0.72μJ.Q-switchedmodelockingwasalsoobtainedintheexperiment.TheresearchresultswillopenupapplicationsofMoS2atthemid-infraredwavelength.
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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:Weexperimentallydemonstratehighopticalqualityfactorsilicamicrodiskresonatorsonasiliconchipwithlargewedgeanglesbyreactiveionetching.For2-μm-thickmicroresonators,wehaveachievedwedgeanglesof59°,63°,70°,and79°withopticalqualityfactorsof2.4×10~7,8.1×10~6,5.9×10~6,and7.4×10~6,respectively,from~80μmdiametermicroresonatorsinthe1550nmwavelengthband.Also,for1-μm-thickmicroresonators,wehaveobtainedanopticalqualityfactorof7.3×10~6withawedgeangleof74°.
简介:Wedemonstratethatferroferric-oxide(Fe3O4)nanoparticlesexhibitnonlinearsaturableabsorptionpropertyat1.55μm,andfabricatetwofilmysaturableabsorbersbyembeddingthenanoparticlesintoapolyvinylalcohol(PVA)filmorpolyimide(PI)filmseparately.IntheFe3O4-PVA(Fe3O4-PI)Q-switchedfiberlaser,thepulserepetitionrateincreasesfrom8.5kHz(5.5kHz)to28kHz(49kHz)andthepulsedurationdecreasesfrom23.5μs(47μs)to6μs(3.5μs)byvaryingthepumppowerfrom25mW(23mW)to150mW(650mW).ExperimentresultsindicatethatPI-basedsaturableabsorberscanaffordlargerpowersthanPVA-basedsaturableabsorbers,whichcanbeattributedtothehigherfusionpointofthePIfilm.TheFe3O4-PIsaturableabsorberexhibitsfeaturesofhighdamagethreshold,lowcost,andgoodflexibility,whichcouldbeappliedinfieldsofnear-infraredpulsegenerationandfrequencyconversions.
简介:WedemonstrateaQ-switchedRamanfiberlaserusingmolybdenumdisulfide(MoS_2)asasaturableabsorber(SA).TheSAisassembledbydepositingamechanicallyexfoliatedMoS_2ontoafiberferrulefacetbeforeitismatchedwithanothercleanferruleviaaconnector.ItisinsertedinaRamanfiberlasercavitywithatotalcavitylengthofabout8kmtogenerateaQ-switchingpulsetrainoperatingat1560.2nm.A7.7-km-longdispersioncompensatingfiberwith584ps·nm~(-1)km~(-1)ofdispersionisusedasanonlineargainmedium.Asthepumppowerisincreasedfrom395mWto422mW,therepetitionrateoftheQ-switchingpulsescanbeincreasedfrom132.7to137.4kHzwhilethepulsewidthisconcurrentlydecreasedfrom3.35μsto3.03μs.Themaximumpulseenergyof54.3nJisobtainedatthemaximumpumppowerof422mW.TheseresultsshowthatthemechanicallyexfoliatedMoS_2SAhasagreatpotentialtobeusedforpuisegenerationinRamanfiberlasersystems.
简介:Inpastyears,rare-earth-dopedfluoridefiberlasers(FFLs)havedevelopedrapidlyinthemid-infrared(mid-IR)region.However,duetothelackoffiberopticdevicesandchallengeoffluoridefibersplicing,mostmid-IRFFLshavebeendemonstratedwithfree-spaceopticelements,limitingtheadvantagesofall-fiberlasersforflexibledelivery,stability,andcompactness.Here,wereport,tothebestofourknowledge,thefirstpulsedall-fiberFFLinthemid-IRregion.Bytakingadvantageoftheintegrationofblackphosphorusflake,stableQ-switchedandmode-lockedpulseswereobtainedat2.8μmwavelength.Webelievethatthisall-fiberdesignwillpromotetheapplicationofpulsedFFLinthemid-IRregion.
简介:PlanarringresonatorwaveguidesarefabricatedinthinfilmsofAs2S3chalcogenideglass,depositedonsilicaon-siliconsubstrates.WaveguidecoresaredirectlywrittenbyscanningthefocusedilluminationofafemtosecondTi:sapphirelaseratacentralwavelengthof810nm,throughatwo-photonphoto-darkeningprocess.Alargephotoinducedindexchangeof0.3–0.4refractiveindexunitsisobtained.Theradiusoftheringresonatoris1.9mm,correspondingtoatransmissionfreespectralrangeof9.1GHz.Ahighloaded(intrinsic)Qvalueof110,000(180,000)isachieved.Thethermaldependenceoftheresonatortransferfunctionischaracterized.Theresultsprovidethefirstreport,tothebestofourknowledge,ofdirectlywrittenhigh-Qringresonatorsinchalcogenideglassfilms,anddemonstratethepotentialofthissimpletechniquetowardsthefabricationofplanarlightguidecircuitsinthesematerials.
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简介:WereportontheoperationofpassivelyQ-switchedwaveguidelasersat1μmwavelengthbasedonagraphene∕WS2heterostructureasasaturableabsorber(SA).ThegainmediumisacrystallineNd:YVO4claddingwaveguideproducedbyfemtosecondlaserwriting.Thenanosecondwaveguidelaseroperationat1064nmhasbeenrealizedwiththemaximumaverageoutputpowerof275mWandslopeefficiencyof37%.IncomparisonwiththesystemsbasedonsingleWS2orgrapheneSA,thelasingQ-switchedbyagraphene∕WS2heterostructureSApossessesadvantagesofahigherpulseenergyandenhancedslopeefficiency,indicatingthepromisingapplicationsofvanderWaalsheterostructuresforultrafastphotonicdevices.
简介:Thisworkpresentsthesaturableabsorption(SA)propertiesofCsPbBr3perovskitequantumdots(QDs).TheperovskiteQDsshowexcellentSAperformancewithanonlinearabsorptioncoefficientof-35×10-2cm∕GWandafigureofmeritof3.7×10-14esucm.Further,theiruseassaturableabsorbersinapassivelyQ-switchedvisiblesolid-statelaserforthegenerationofsolitonpulsesisdemonstrated.TheseresultsdemonstratethepotentialfortheperovskiteQDstoactassaturableabsorbers.