coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation chao feng资料.pdf

该【coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation chao feng资料 】是由【dt83088549】上传分享，文档一共【7】页，该文档可以免费在线阅读，需要了解更多关于【coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation chao feng资料 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。ELERATORSANDBEAMS22,050703(2019)Coherentextremeultravioletfree-electronlaserwithecho-enabledharmonicgenerationChaoFeng,HaixiaoDeng,MengZhang,XingtaoWang,SiChen,TaoLiu,KaishangZhou,DuanGu,ZhenWang,ZenggongJiang,XuanLi,BaoliangWang,WenyanZhang,TaiheLan,LieFeng,BoLiu,QiangGu,YongbinLeng,LixinYin,DongWang,andZhentangZhao*ShanghaiAdvancedResearchInstitute,ChineseAcademyofSciences,Shanghai201210,ChinaGuangleiWangStateKeyLaboratoryofMolecularReactionDynamics,DalianInstituteofChemicalPhysics,ChineseAcademyofSciences,Dalian116023,People’sRepublicofChinaDaoXiangKeyLaboratoryforLaserPlasmas(MinistryofEducation),SchoolofPhysicsandAstronomy,ShanghaiJiaoTongUniversity,Shanghai200240,China(Received27February2019;published17May2019)Theecho-enabledharmonicgeneration(EEHG)-electronlaser(FEL)atanextremeultraviolet(EUV)wavelengthwithaseededFELfacility,theShanghaisoftx-,,.,generationofveryhighharmonicswithasmalllaser-inducedenergyspreadandinsensitivitytobeamimperfections,:.-electronlasers(FELs)thatareabletoprovideshort-wavelengthFELswithexternallasersatultraviolettunablehigh-powercoherentradiationhaveawidearray(UV)wavelengthstogeneratestableandfullycoherentofapplicationsinbiology,chemistry,physics,andmaterialradiation[12–28].Thesetechniquesallrelyonproducingscience[1].Severalx-ess-[2–9],whichmarksthehigh-gainharmonicgeneration(HGHG)[12,13]technique,beginningofaneweraofx--raysinusoidalenergymodulationinbeamlongitudinalphasewavelengthrange,mostoftheFELfacilitiesareoperatedspaceisfirstproducedthroughalaser-electroninteractionwiththeself-amplifiedspontaneousemission(SASE)inashortundulator(modulator).Afterpassingthroughaprinciple[10,11].WhiletheSASEschemeallowsFELsmallchicane,theenergymodulationisconvertedintolasingatasubangstromwavelength[4],ponentattheratherlimitedtemporalcoherence,,thedensity-(radiator)applicationssuchasresonantscatteringandspectroscopicwherethebunchingproducesacoherentsignalthatistechniquesthatrequire,orcouldbenefitfrom,*******@,single-stageHGHGFELshavelimitedfrequencyup-conversionefficiency[13].Asaresult,multiplestagesPublishedbytheAmericanPhysicalSocietyunderthetermsofofHGHGaretypicallyrequiredtoreachx-.–FurtherdistributionofthisworkmustmaintainattributiontostartingfromaUVseedlaser[1719],andthestability,intheauthor(s)andthepublishedarticle’stitle,journalcitation,general,hasanincreasedsensitivitytobeamfluctuationsandDOI.[19].Furthermore,thecentralwavelengthandbandwidthof2469-9888=19=22(5)=050703(7)050703-,050703(2019)aHGHGFELaresensitivetobeamimperfections,inourexperimentalresultsclearlyshowthehigher-frequencyparticular,linearandnonlinearenergychirps[29,30].up-conversionefficiencyandlesssensitivitytobeamewiththeecho-imperfectionsofEEHGandpavethewaytowardscoher-enabledharmonicgeneration(EEHG)technique[20,21],ent,intense,-,eleratoroftheSXFELconsistsofaphoto-,injector,alinacwithS-bandandC-eleratorthehighlynonlinearphasespacemanipulationprocessstructures,-to670MeVwithatransverseemittanceofabout2μmradtudinalphasespace,-rayradiationTheseadvantageshavestimulatedworldwideeffortsinfroma266nmconventionalseedlaserthroughatwo-stageexploringthepotentialoftheEEHGtechniqueforpro-cascadedHGHGscheme,-of-consistsofamodulator,adispersionsection,(FB)15thharmonic[24–26]hicane.(～350nm)[27]withaseedlaserinthefar-infrared(FIR),coherentemissionwiththeEEHGtheexistingundulatorsystemhavebeenstudiedwithtechniqueatthe75thharmonic(～32nm)ofa2400nmnumericalsimulationsbeforetheexperiment[32].Bothseedlaserwasalsoreported[28].Whilethebasicphysicsoptionsusethetwomodulator-chicanemodulesinthetwobehindtheEEHGschemehasbeendemonstratedwithastagestoproducetherequiredenergymodulationandFIRseedlaser,,,,experimentswithrealisticparam-,forthissetup,simulationresults[32]indicateetersets,.,pressedelectronthattheintrabeamscattering,longitudinalspacecharge,beamwithahighpeakcurrent,arehighlydesiredtoandsecond-ordertransporteffectsinthelongdriftsectiondemonstratethefullfeasibilityofEEHGforanx-,DS1andR1HerewereportthefirstlasingofanEUVFELat24nmwereturnedoff,-rayFELfacility(SXFEL),because[31].ThelasingwavelengthisoneorderofmagnitudenofinestructuresaregeneratedbeforetheFBchicane,-,withthisexperi-mentisbasedonthesecondoption,,whereuistheperiodlength,pistheparingwithHGHG,periodnumberofonesegmentundulator,,injectionchicane;M,modulator;FB,fresh-bunchchicane;DS,dispersionsection;R,-2COHERENTEXTREMEULTRAVIOLET…,050703(2019)?e1=?jJae?aABTej;e1TElectronbeambn;m?jJnf?A1?nB1teKmtnTB2?JmBeamenergy500–670MeV2?e1=2T?nB1teKmtnTB2?Bunchcharge500pC×??eKmtnTA2B2?gej;e2TSliceenergyspread30–40keVProjectenergyspread1MeVwhereAistheenergymodulationamplitudedividedbytheProjectemittance2mmmradσBRkσ=Ek>500energyspreadE,?56E,isthewavenumberofPeakcurrentAKk=kaBunchlength(FWHM)1pstheseedlaser,?21,umberforHGHG,anda?,theoptimizedconditionismoreSeedlaserwavelength266nmcomplicatedforEEHG,whosebunchingfactorisdeter-Seedlaserpulselength(FWHM)×λuforM120×8cmparingthebunchingfactordistributionsp×uforM2×.cmofHGHGandEEHGoveroneoctaveinfrequencyintheNp×λuforR120×,viadirectmeasurementofthecoherentRR10–10mm56ofDS1(56)–2mm56ofDS2(56)benchmarkingthetheoryinsuchalargeparameterspace,weremovedthefirstundulatorsegmentofR2()andreplaceditwithanundulatorwithalongerperiod(U40)fromR1,(–44nm)icgapfromparametersfortheparametersettingofEEHGistheslice–,whichismeasuredtobeabout3040keVTheintensityofthecoherentradiationisproportionaltothe(pressionratios)bythecoherentsquareofthebunchingfactorandcanbedetectedbytheharmonic-generation-basedmethod[33].(seed1andseed2),,whichwillbe1helpfultoillustratethesensitivityoftheFELoutputto(a)-,which1(b)consistsofafluorescencescreenfordetectingtheFELtransversespot,,andaspectrometerthatcancoverthewavelengthrangeof5–[](c)Asmentionedabove,thekeyadvantageofEEHGis,,verysmall-,umbertheup-conversionefficiencywillbeenhancedonlyfortheR1=R2targethighharmonics,,thebunchingfactorofHGHGshowsexpo-umbersforsingle-,andbunchingatmanyharmonicswillall(a)HGHG:A1?0,A2?,R56?,andR56?-conversionefficiencycan90μm;(b)EEHG:A1?,A2?,R56?,and21bequantifiedbythebunchingfactor,whichcanbeR56?90μm;(c)EEHG:A1?,A2?,R56?,2calculatedforHGHGandEEHGby[12,21]andR56?-,050703(2019)1ordinglydelayed),(c),inagreementwiththescalinga～R56=,whichmeansthatthebunchingfactorofEEHG2radiationpowerwiththeR56ofaround90μm,-indicatesanenergymodulationamplitudeofaboutmentresultscoincidewiththetheoreticalpredictionsandordingtoEq.(1).Afterthat,,.(2)2222indicatesthat,ingeneral,therearemultipleparametersetscoherentradiationisproportionaltoKR?JJ?ba,,manyisthedimensionlessundulatorparameterand?JJ??2222islandscouldbeseeninthebunchingdistributionofJ0?KR=e4t2KRT??J1?KR=e4t2KRT?,withA1??,?JJ?(a).Figure3(b)photodiodefordifferentwavelengths,wefoundthattheshowsthemeasuredradiationintensityatthe20thhar-,(a),whichfits56radiationisobservedonlyattheoptimizedR2valueofquitewellwiththecalculationsbasedonEq.(1)