简介：Grapheneisaone-atom-thickplanarsheetofsp2-hybridizedorbitalbondedhoneycombcarboncrystal.Itsgaplessandlinearenergyspectraofelectronsandholesleadtotheuniquecarriertransportandopticalproperties,suchasgiantcarriermobilityandbroadbandflatopticalresponse.Asanovelmaterial,graphenehasbeenregardedtobeextremelysuitableandcompetentforthedevelopmentofterahertz(THz)opticaldevices.Inthispaper,thefundamentalelectronicandopticpropertiesofgraphenearedescribed.Basedontheenergybandstructureandlighttransmittancepropertiesofgraphene,manynovelgraphenebasedTHzdeviceshavebeenproposed,includingmodulator,generator,detector,andimagingdevice.Thisprogresshasbeenreviewed.FutureresearchdirectionsofthegraphenedevicesforTHzapplicationsarealsoproposed.

简介：Thereentrytrajectoryplanningforhypersonicvehiclesiscriticalandchallenginginthepresenceofnumerousnonlinearequationsofmotionandpathconstraints,aswellasguaranteedsatisfactionofaccuracyinmeetingallthespecifiedboundaryconditions.Inthelasttenyears,manyresearchershaveinvestigatedvariousstrategiestogenerateafeasibleoroptimalconstrainedreentrytrajectoryforhypersonicvehicles.Thispaperbrieflyreviewsthenewresearcheffortstopromotethecapabilityofreentrytrajectoryplanning.Theprogressoftheonboardreentrytrajectoryplanning,reentrytrajectoryoptimization,andlandingfootprintissummarized.Themainchallengesofreentrytrajectoryplanningforhypersonicvehiclesareanalyzed,focusingontherapidreentrytrajectoryoptimization,complexgeographicconstraints,andcooperativestrategies.

简介：RecentresearchprogressesinMulti-BeamKlystron(MBK)inIECASarebrieflyintroducedintheletter.TheS-bandMBKsofIECAShavepeakpowerof120-250kW,averagepowerof4-9kW,efficiencyof35-45%,gainof41-46dB,beamvoltageof15-19kV,andweightof40-45kg.SomekeytechnicalproblemsofMBKarealsodescribedanddiscussed.Amongthem,improvingthedesignofMBKtoobtaintherequiredbandwidth,raisingbeamtransmissiontoincreaseaveragepower,eliminatingoscillationandsprayspectrum,overcomingwindowbreakdowncausedbymagicmode,reducingbreakdowntimesofelectrongun,aremostimportantthingsforthepracticalMBK.Besides,furtherresearchworkinMBKinIECASiscommented.

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简介：Areviewontheprogressofpowerful2μmsilicafibersourcesinpastdecadesispresented.Wereviewthestate-of-the-artrecordsandrepresentativeachievementsof2μmhigh-average-powercontinuouswave,pulsedfiberlasersandamplifiers,andpowerfulsuperfluorescentsources.Challengeswhichlimitthefurtherpowerscalingof2μmsilicafibersourcesarediscussed,includingpumpingbrightnesslimitation,thermalproblem,andnonlineareffects.Potentialandpromisingroadmapstogobeyondtheselimitations,liketandempumpingandbeamcombining,arediscussed.Prospectsofpowerful2μmsilicafibersourcesarealsopresentedintheendofpaper.

简介：InGaN-basedlight-emittingdiode(LED)asforthereplacementofconventionalfluorescentlightingsourcestillneedsagreatefforttoimprovethelight-extractingefficiencyaswellasinternalquantumefficiencyofLEDs.Surfaceplasmontechnologyhasrecentlyattractedconsiderableinterest,becausethespontaneousemissionrateandthelightextractionefficiencyofalight-emittingdevicecanbesimultaneouslyenhancedthroughthecouplingbetweenanInGaNquantumwellandsurfaceplasmons.Thesurfaceplasmon-emittercouplingtechniquewouldleadtohighbrightnessmultichipwhiteLEDsthatofferrealisticalternativestoconventionalfluorescentlightsources.Inthisarticle,thepossibleenhancementmechanismofsurfaceplasmonisdiscussed,andthenrecentdevelopmentsofsurface-plasmon-enhancedlight-emittingdiodeareintroduced.

简介：Wepresenttherecentresearchprogressesofourgrouponmid-infraredpulsedfiberlasersat3μmbypassiveswitching.Threedifferentkindsofsaturableabsorbersincludingsemiconductorsaturableabsorber(SESAM),Fe2+:ZnSecrystal,andtopologicalinsulator(TI)wereusedtoperformthepulsegeneration,respectively.Thetemporalregimesofmodelocking,Q-switching,andQ-switchinginducedgainswitchingweregained.Somerelativediscussionsandprospectiveeffortsareproposedattheendofthispaper.