简介：Graphenemicrofibersareburgeoningmodulatorswithgreatpotentialinall-opticalcommunication.Oneofthecriticalissuesthatremainstobeunderstoodisthedynamicmechanismoflight–grapheneinteraction.Here,weproposeapowerdependentmodulationbyusing980nmpumplightand1064nmsignallightviagraphenemicrofiber,andtheresultsshowastrongtransmissionreductionandfrequencyblueshiftwiththeincreaseofpumppower.TheexperimentalobservationisattributedtoastimulatedBrillouinscatteringprocessinducedbythepumplight.Powerandfrequencyvariationsarearesultofenergytransitionofthescatteredphononinthefiber.Thisworkrevealsthenonlineareffectprocessinthelight–grapheneinteractionandprovidesanewmethodforpowerandfrequencycontrolwithgrapheneall-opticalmodulation.

简介：Weexperimentallydemonstratetwokindsofallfew-modefiber(FMF)ringlaserswithhigh-ordermode(HOM)oscillationinthelasercavity.Onekindisaswitchable-wavelengthall-FMFHOMlaserwithanoutputoftunableopticalvortexbeams(OVBs);theotherisaQ-switchedall-FMFHOMlaserwithanoutputofpulsedcylindricalvectorbeams(CVBs).Thelasersarecomposedofall-FMFcomponentsandfew-modeerbium-dopedfiber.ASagnacinterferometermadeofa3dBFMFcouplerfunctionsasthewavelengthselector,andswitchablemultiwavelengthtunableOVBsareexperimentallyrealized.Carbonnanotube-basedsaturableabsorbersandthenonlinearpolarizationrotationtechniqueareusedtoachieveQ-switchedCVBlasers.Thisisthefirstreport,toourknowledge,onthegenerationofswitchable-wavelengthandQ-switchedHOMbeamsinall-FMFlasercavities.

简介：Ahybridno-corefiber(NCF)–gradedindexmultimodefiber(GIMF)structureisusedasasaturableabsorber(SA)formode-lockedlaseroperation.SuchanSAsupportsvarioustypesofsolitonoutputs.Bychangingthecavityparameters,notonlythespatiotemporalmode-lockingstateswithastablesinglepulsebutalsotightlyandlooselyboundsolitonsaregenerated.Single35.5pJsolitonscenteredat1568.5nmhavea4nmspectralfull-widthathalf-maximumandan818fstemporalduration.Tightlyboundsolitonpairswithcontinuouslytunablewavelengthfrom1567.48nmto1576.20nm,featuredwithan~700fspulsetrainwithaseparationof2.07ps,havebeenobservedbystretchingtheNCF-GIMFstructureddevice.Meanwhile,severaldifferentpulseseparationsfrom37.57psto56.46psoflooselyboundsolitonshavealsobeenrealized.Theresultsprovidehelpinunderstandingthenonlineardynamicsinfiberlasers.

简介：Wehavestudiedaswitchablehyperbolicmetamaterialcomposedofagraphene–dielectricperiodicstructure.Bytuningthechemicalpotentialofallgraphenesheetssimultaneously,theisofrequencycurvecanswitchbetweenanellipseandahyperbolaconveniently.Inparticular,aspecialhyperbolicisofrequencycurvewithitsasymptoteperpendiculartotheinterfaceisobtainedandusedtorealizethezeroreflectioneffect.Furthermore,azeroreflection-basedopticalswitchworkingintheterahertzspectrumisdemonstrated.Itsbandwidthcanbeefficientlyadjustedbygeometricparameterssuchaspermittivityandperiod.Suchanopticalswitchpossessesthemeritsoflowloss,hightransmittancecontrast,highresponsespeed,compactsize,hightoleranceofchemicalpotential,andhavingallincidentangles(0°–90°)simultaneously.Suchanopticalswitchholdsgreatpotentialinmanyfields,suchasdatastorage,beamsteering,andintegratedphotoniccircuits.

简介：Wepresenthereaseriesofperylenediimide(PDI)basedisomericconjugatedpolymersfortheapplicationasefficientelectronacceptorsinall-polymersolarcells(all-PSCs).BycopolymerizingPDImonomerswith1,4-diethynylbenzene(para-linkage)and1,3-diethynylbenzene(meta-linkage),isomericPDIbasedconjugatedpolymerswithparallelandnon-parallelPDIunitsinsidebackboneswereobtained.Itwasfoundthatpara-linkedconjugatedpolymer(PA)showedbettersolubility,strongerπ-πstacking,morefavorableblendmorphology,andbetterphotovoltaicperformancethanthoseofmeta-linkedconjugatedpolymers(PM)did.DevicebasedonPTB7-Th:PA(PTB7-Th:poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl})showedsignificantlyenhancedphotovoltaicperformancethanthatofPTB7-Th:MA(3.29%versus0.92%).Moreover,thephotovoltaicperformanceofthesepolymericacceptorscouldbefurtherimprovedviaaterpolymericstrategy.Bycopolymerizingasmallamountofmeta-linkagesintoPA,theoptimizedterpolymericacceptorsenabledtoenhancephotovoltaicperformancewithimprovedtheshort-circuitcurrentdensity(Jsc)andfillfactor(FF),resultinginanimprovedpowerconversionefficiency(PCE)of4.03%.

简介：Wedemonstrateapassivelymode-lockedall-fiberlaserincorporatingapieceofgraded-indexmultimodefiberasamode-lockingmodulatorbasedonanonlinearmultimodalinterferencetechnique,whichgeneratestwotypesofcoexistinghigh-energyultrashortpulses(i.e.,theconventionalsoliton(CS)andthestretchedpulse(SP))TheCSwithpulseenergyashighas0.38nJisobtainedatthepumplevelof130mW.Whenthepumpincreasesto175mW,thehigh-energySPoccursatasuitablenonlinearphasebiasanditspulseenergycanreach4nJata610mWpump.ThepulsedurationsofthegeneratedCSandSPare2.3psand387fs,respectively.Thetheoryofnonlinearfiberoptics,single-shotspectralmeasurementbythedispersiveFourier-transformtechnique,andsimulationmethodsbasedontheGinzburg–LandauequationareprovidedtocharacterizethelaserphysicsandrevealtheunderlyingprinciplesofthegeneratedCSandSP.Aroguewave,observedbetweentheCSandSPregions,mirrorsthelaserphysicsbehindthedynamicsofgeneratingahigh-energySPfromaCS.Theproposedall-fiberlaserisversatile,cost-effectiveandeasytointegrate,whichprovidesapromisingsolutionforhigh-energypulsegeneration.

简介：WedemonstrateastableconventionalsolitoninaTm-dopedhybridmode-lockedfiberlaserbyemployingahomemadeall-fiberLyotfilter(AFLF)andasingle-wallcarbonnanotube.TheAFLF,designedbysandwichingapieceofpolarization-maintainedfiber(PMF)withtwo45°tiltedfibergratingsinscribedbyaUVlaserinPMFwithaphase-maskscanningtechnique,showslargefilterdepthof~9dBandsmallinsertionlossof~0.8dB.ByoptimizingthefreespectralrangeoftheAFLF,theKellysidebandsofaconventionalsolitoncenteredat1966.4nmcanbedramaticallysuppressedwithoutimpairingthemainshapeofthesolitonspectrum.Itgivesthepulsedurationof1.18psandbandwidthof3.8nm.ByadjustingthetemperatureofthePMFoftheAFLFfrom7°Cto60°C,wavelengthtunablesolitonpulsesrangingfrom1971.62nmto1952.63nmarealsoobtained.Thegeneratedsolitonpulsescanbepreciselytunedbetween1971.62nmand1952.63nmbycontrollingthetemperatureoftheAFLF.

简介：Thesuppressionoftherecombinationofelectronsandholes(e–h)andtheenhancementofthelightabsorptionofsemiconductorsaretwokeypointstowardefficientphotocatalyticdegradation.Here,wereportafew-layerg-C3N4/α-MoO3nanoneedles(flg-C3N4/α-MoO3NNs)all-solid-stateZ-schememechanismphotocatalystsynthesizedviaatypicalhydrothermalmethodinacontrolledmanner.Therecombinationofthephoto-inducede–hpairscouldbeeffectivelyrestrainedbytheZ-schemepassagewaybetweentheflg-C3N4andα-MoO3NNsinthecomposite,whichcouldalsopromiseahighredoxabilitytodegradepollutants.Anditbecamepossibleforthepreparedphotocatalysttoabsorblightinawiderangeofwavelengths.Thedetailedmechanismwasstudiedbyelectronspin-resonancespectroscopy(ESR).Thelow-dimensionalnanostructureofthetwoconstituents(α-MoO3NNswithone-dimensionalstructureandflg-C3N4withtwo-dimensionalstructure)endowedthecompositewithvarietiesofexcellentphysicochemicalproperties,whichfacilitatedthetransferanddiffusionofthephotoelectronsandincreasedthespecificsurfaceareaandtheactivesites.The10wt%flg-C3N4/α-MoO3NNsshowedthebestphotocatalyticperformancetowardRhBdegradation,therateofwhichwas71.86%,~2.6timeshigherthanthatofα-MoO3NNs.

简介：WereportQ-switchedandmode-lockederbium-dopedall-fiberlasersusingternaryReS2(1-x)Se2xassaturableabsorbers(SAs).ThemodulationdepthandsaturableintensityofthefilmSAare1.8%and0.046MW∕cm2.InQ-switchedmechanismoutput,thepulsewascenteredat1531.1nmwithmaximumpulseenergyandminimumpulsewidthof28.29nJand1.07μs,respectively.Inmode-lockedoperation,thepulsewascenteredat1561.15nmwithpulsewidthof888fs,repetitionrateof2.95MHz,andmaximumpulseenergyof0.275nJ.Tothebestofourknowledge,thisisthefirstreportonthemode-lockedEr3+-dopedfiberlaserusingternarytransitionmetaldichalcogenides.Thisworksuggestsprospective2D-materialSAscanbewidelyusedinversatilefieldsduetotheirattractiveoptoelectronicandtunableenergybandgapproperties.