镁对掺铒铌酸锂晶体光谱性质的影响

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1、天津大学硕士学位论文镁对掺铒铌酸锂晶体光谱性质的影响姓名：杨庆忠申请学位级别：硕士专业：光学工程指导教师：张德龙20090701ABSTRACTLithiumniobatemiNb03)hasbecomeamostcommoncrystalmaterialtofabricatewaveguideforitsphysicalproperties．ManyimportantpropertiesstronglydependonthecompositionandlatticedefectsinsidetheLithiumniobatecrysta

2、l．DeepMgOdopedEr：LiNb03canenhance1．5umemissionandsuppressgreenupconversionemission．Sincethewaveguideamplifierandlaserat1．549miscommonlyconcernedandstudied，itisgreatlynecessarytostudytheeffectsandmechanismofactionaboutdeepMg—dopingtoEr：LiNbOs．Someexperimentalresultsarereac

3、hedinthisarticle．Theseexperimentalcanofferconsiderableguidancetofurtherworkinthefuture．Themainworkofthedissertationcanbesummarizedasfollowingthreeaspects：1．AtroomtemperatureYcutEr(1m01％)：LiNb03unpolarizedabsorptionspectrumwithseveralMgO-codopedconcentration(2，4，6，8m01％)we

4、remeasured，andanobviousblueshiftofMgdopedLiNb03opticalabsorptionedgewasobserved．WiththegrowthofMgconcentration，integralquantitiesofabsorptioncoefficientinabsorptionbanddecreasewhichshowsMgdopingrestrainstheabsorptionofeachenergylevel．Theunpolarizedabsorptionspectrumwasana

5、lyzedwithJ—Otheory,ExperimenmlandtheoreticalvalueofEr3+electronicstransitionintensionisobtainedatdifferentMgconcentrationdopedrespectively．2．Byusinga800rimfemtosecondlaserexcitationsource，time-resolvedspectroscopystudyshowsthatthedecaytraceofthegreenupconversionemiissiono

6、ftheEr／Mgcodopedcrystalisobviousnonexponentialandthresholdeffect．thesespectroscopiccharachacteristicsareaSsociatedwiththehigherconcentrationoftheclustersitesofEr+ion．thehighernonradiativecrossrelaxation．AndhencethepopulationsofthelowerlocatedmanifoldsoftheErion，suchasthe4

7、113／2(1．5urn)manifoldresultinginenhancing1．5umemissionandsimultaneouslysuppressinggreenupconversionemission．3．TheimpactsofdopingMgonthemicrocosmicdefectstructureofMgO—dopedLiNb03crystalhavebeeninvestigated．TheexistingMg-dopingmodelshavebeenanalyzedandcompared，basedonwhich

8、weintroducesomeimprovements．Accordingtotheimprovedmodelandexperimentaldata，wededucethatthenumber