太赫兹应用技术研究

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1、浙江大学硕士学位论文太赫兹应用技术研究姓名：张兴宁申请学位级别：硕士专业：检测技术与自动化装置指导教师：周泽魁20050201浙江大学硕士学位论文Terahertz(THz)wavesarethosewithfrequenciesbetween300GHzto10THzWiththelocationofthespectrumbetweentheelectronicandphotonicdomains,THzwavescontainrichinformationinvolvedinmolecularvibrationandrotation,andhavesub-picosecond

2、pulsewidth,lowphotonenergyandhighspace-timecoherence.Theseuniquefeaturesareindeedtremendousandimplyastonishingapplicationsinvariousareasofsciencesuchasastronomy,biology,computersandcommunications.Duringrecent20years,agreatdealstudiesdevelopedquicklycoveringTHzgeneration,detectionandapplicatio

3、ns.ThisthesisresearchedmainTHzapplicationtechniquesnowadaysbasedonthereadingoflotsofdocuments.Thedetailsareasfollows:AnalyzethemainmethodsandtechnologiesforTHzgeneration,detectionandprocessing,andfocusonthephysicalprinciplesandefectsonwhichthesetechniquesarebased.Atthesametime,THztime-domains

4、pectroscopy(THz-TDS)andTHzcomputedtomography(THzCT)arestudiedindetail.StudythewaytoextractsampleparametersfromTHzwaveforminTHz-TDSandgivethesimulationstudy.Onthebaseofasetofknownsignals,wegettheidealcurvesofrefractionandabsorptioncoeficientsusingFouriertransformandtransmissionspectroscopymode

5、l.More,someinfluencingfactorsarediscussed.AnalyzetheerrorcausedbysmallchangesoftheopticalpathofTHzbeaminreflectionspectroscopy.Thesechangestakeplaceduetoreplacementofthesample.Bothqualitativeandquantitativeanalysesaregiven.Andintroduceakindofimprovedmethodtoreducethemeasurementerrorefficientl

6、y.IntroduceahighresolutionalgorithmforTHztwo-dimensionalCT,whichtakesadvantageofWienerfilteringandfitstheimagingsystemofTHzCT.AsimulationforaTHzCTimageshowsthatthisalgorithmcangreatlyimproveitsresolution.Introducethedesignschemeofaninfraredsimulationsystem.ConsideringthehighcostofaTHzCTsystem

7、,itisreasonableandfeasibletoestablishalowcostinfraredCTsystemforsimulationstudycurrently.Thissystemmakesuseofsector-scanningmodelandhasthreesubsystems.Algebrareconstructiontechnique(ART)isemployedinthissystemandprovedhavinggoodperformanceinim