金属及金属-半导体核壳结构纳米颗粒复合薄膜的超快光物理研究

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1、复旦大学硕士学位论文金属及金属—半导体核壳结构纳米颗粒复合薄膜的超快光物理研究姓名：刘烨申请学位级别：硕士专业：光学指导教师：钱士雄20030428论文摘要5、采用飞秒泵浦一探测技术对Au@CdS球壳结构纳米颗粒复合的BaTi03薄膜的超快动力学进行了研究。发现了超快的漂白建立过程和～个双指数恢复过程(‘。“90fs、L一肿“2．3ps，％一砷>200ps)，这分别是由电子一电子散射、电子一声子散射和声子一声子散射引起的。另外，我们还研究了电子一声子散射时间常数t一。随泵浦功率增大而减小的关系，这可能是由光生热电子的温度不同所造成的。关键词：纳米颗粒，飞秒激光，光学Ker

2、r效应，泵浦一探测，三阶光学非线性ⅡABSTRACTNanometer-sizedmetalandsemiconductorparticleshavedrawnconsiderableattentioninrecentyearsbecauseoftheirlargethird·orderopticalnonlinearityandultrafastnonlinearopticalresponse，whicharethecentraltofutureopticaldeviceapplications．Thesynthesisofmetal—semiconductorcomp

3、ositenanoparticlesprovidedanewwaytOtailortheopticalandelectronicpropertiesofmetalandsemiconductornanoparticles．Especially，core—shellstructurecompositenanoparticlesoftenexhibitimprovedphysicalandchemicalpropertiesovertheirsinglecomponentcounterparts，andhencearepotentiallyusefulinabroaderra

4、ngeofapplications．Byincorporatingcompositenanoparticlesintomatrix，novaopticallyfunctionalandtransparentfilmsCanbepreparedandappliedinvariousfieldssuchasallopticalnetwork，opticaldatastorageandopticalcomputing．Inthisthesis，themetalandmetal-semiconductorCOre—shellcompositcnanoparticlesWCl-ei

5、ncorporatedintoTi02andBaTi03thinfilms，respectively．Theirlinearandnonlinearopticalpropertieswerestudied．Themainresultsarelistedasfollowing：1．Inordertosetupenoughbackgroundknowledgeaboutultrafastspectroscopy,firstofall，weintroducethegenerationoffemtosecondlaserpulses，theultrafastspectroscop

6、yexperimentaltechniquesandtheirprinciples，andtheapplicationsofthesetechniquesinphysicalandchemicalresearch．2．Byusingfemtosecondtime-resolvedopticalKerreffect(OKE)technique，Wehavemeasuredthethird-ordernordinearopticalsusceptibilitiesofAunanoparticlesembeddedinTiO：thinfilms(Au：Ti02)．Alarge∥

7、valuewasreported．Wefoundthatthe∥)valuesofAu：Ti02increasewiththeincreaseofannealtemperature．Weattributedtheannealtemperature·dependantpropertiestotheincreasedvolumefractionsofAunanoparticles．WealsoinvestigatedtheultrafastdynamicsofhotelectronsrelaxationinAu：Zi02thinf