Femtosecondtransientabsorption飞秒瞬态吸收

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1、FemtosecondtransientabsorptionPumpandprobetechniqueSchematiclayoutofatypicalfemtosecondtransientabsorptionapparatusMainpartsoftheinstrumentExcitationsourceProbesourceOpticaldelayDetectorPumpProbett<0t=0t>0PumpandprobeconceptI0I1TransientsignaldetectionTypicaltemporalcharacteristics~100fstim

2、eresolutionDeterminedbythelaserpulseduration1-6nstimewindowDeterminedbytheopticaldelaylengthExcitationlightsourcesDirectTi-Sapphirelaseroutput800nmHarmonicgenerationSHG400nmTHG267nmOpticalparametricamplification250-12000nmProbelightsourcesWhitelightcontinuumgenerationAdvantageEasytouseAllwa

3、velengthsaregeneratedatonceDisadvantageSomewhatlimitedspectralrange330-1000nmProbelightsourcesOpticalparametricamplificationAdvantageBroadspectralrange250-12000nmDisadvantageRequiresmoresophisticatedequipmentOnlynarrowspectrumisgeneratedatonce,therefore–needtoscanThemethodallowsfor:Directob

4、servationofatransientbymonitoringacharacteristicspectralsignatureObservationoftheelectronicandvibrationalenergyredistributionProbingbroadspectralandtemporalrangeinautomatedmodeObservationofstimulatedemissionThemethoddoesnotallowfor:DirectobservationofemissionMonitoringofstructuralchangesDet

5、ectors(CCD)Detectors(CCD)AdvantagesAcquiresthewholespectrumatonceCompactDisadvantagesReducedspeedofdataacquisitionMoreexpensiveDetectors(diodes)Detectors(diodes)AdvantagesAllowsforfasterdataacquisitionLowercostDisadvantagesLimitedtoasinglewavelengthRequiresamonochromatorThesetupwithdiodesis

6、generallymuchmorespaceconsumingTypicaldataexampleTypicaldataexample