对原子系统单光子和双光子电磁诱导透明谱的研究

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1、Studyonatomicsingleandtwo·-photonelectromagneticallyinducedtransparencyspectraMajor：ParticlePhysicsandNuclearPhysicsPostgraduate：ZhangFengSupervisor：HouBang．pin·AbstractElectromagneticaUyinducedtransparencyisoneoftheimportantphenomenaofinteractionbetweenlighta

2、ndatomicsystem．Ingeneral，lightcanbeabsorbedbytheatomicsystemwhenthelightinteractswithmedium．This。’phenomenonisthetransparencyforaprobefieldthroughatomicsystemwhichisdrivenbyastrongcouplingfield．Itisduetothequantuminterferenceinducedby：卷^thecouplingfieldwhichis

3、appliedontheatom．ThereappearmanyinterestingphysicalphenomenatogetherwithEIT,suchaslasingwithoutinversion，largedispersionwithoutabsorption，giantopticalnonlinearityatlowphotonlevel，propagationatslowvelocity,andSOon．Atthesametime,theconceptofEIThasbeengeneralized

4、bymanyresearchers．TheEITinthethree．1evel(includingA，Vand互一type)atomicsystemhasbeengeneralizedtothatinfour-levelormorelevelthanfour-levelatomicsystem．ThesingleEIT(nearafrequency)hasbeengeneralizedtodoubleormulti—plyElFwhichsimultaneouslyhappensatdifferentfreque

5、ncy．Thesingle-photonEIT(onlyforasingleprobefield)hasbeengeneralizedtomulti-photonEIT(fortwoormorefields)．Thisplaysallimportantroleinmulti·channelandquantumcommunication．Inthepresentthesis，weappIycoherentfields(microwavefields)tomodulatethesingleortwo。photontra

6、nsparencyspectra,whichcallleadtothetransparencywithmulti．transparencyⅡI●windoWs．ThewidthoftransparencywindowandthefrequencyatwhichtheEITiscreatedcanbemodulatedbyadjustingthestrengthordetuingforthecoherentfield．Inchapter1，theelectromagneticallyinducedtransparen

7、cyphenomenonanditsdevelopmentareintroduced．Inchapter2，twoandthree-levelatomsalechosenasexamplestodescribetheinteractionbetweenlightandmediumbyusingsemi．classicaltheory,andthentointroducetheEITphenomenon，whichisphysicallyexplainedbyusinginterferencepaths，dresse

8、dbasisanddensitymatrix·Inchapter3，afive—levelatomisproposed．Wehavefoundthatsomeabsorptionpeaksareinducedbyusingtwocoherentfields，whichsplittheEITwindowintothreeparts．Theheightofthe