铌酸锂晶体周期极化及其倍频特性研究

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1、南开大学硕士学位论文铌酸锂晶体周期极化及其倍频特性研究姓名：陈亚辉申请学位级别：硕士专业：光学指导教师：姚江宏20040420AbstractInthisdissertation，theperiodicallypoledcharacteristicsofZ-cutLiNb03dopedwith5tool％MgO(Mg：LN)andnear·stoichiometricLiNb03(Mg：SLN)crystalsdoped1．8t001．％MgOwereinvestigated．Thequasi·phase。matehed(QPM)secon

2、dharmonicgeneration(gHG)basedontheperiodicallypoledMg：LNandMg：SLNwerealsoinvestigated．111eresearchfindingsaredescribedinbriefasfollows：(1)ThetunabilityandtoleranceofQPMSHGinthebulkperiodicallypoledMg：LNandMg：SLNwereanalyzedThegratingperiodbandwidthandthepumpedspectralbandw

3、idth[fullwidthathalfmaximum(FWHM)]werefoundtobeinversedwiththeeffectivelengthinQPMSHG．(2)ThccharacteristicsoftheferroelectricdomaininversioninZ-catLiNb03dopedwith5m01．％MgO(Mg：LN)wereexamined．Thelowestpolarizationswitchingfield玩inMg：LNisaboutSkV／mm．Therealignmentprocessofth

4、einternalfieldinMg：LNisalsoinvestigated．Usingthespontaneousdomainsbackswitching，auniformsubmicrondomainpatterningwithaperiodof1．7umwassuccessfullyfabricated．(3)Thedomainreversalcharacteristicsofnear-stoichiometrieLiNb03wereexaminedandtheswitchfieldfor180。ferroelectricdomai

5、nreversalin*henear-stoichiomentLiNb03crystaldecreaseswith[Li]／[Li+Nb】ratio．Thcswitchfieldinthecrystal丽m[Li】／[Nb]ratioequalto49，9％wasonly3．箨kV／ram．(4)FollowingtheLivacancymodel，weexplainthereasonsofthedramaticdecreaseoftheswitchingfieldinMg：LNandMg：SLN．Wethoughtthereducibil

6、ityofLivacancyandanti—siteNbLi”defectsresultsinthedecreaseoftheswitchingfield．(5)Uniformlyperiodicdomainstructureina1．0mmthickslabofMg：LNandMg：SLNwerefabricated．UsingaQ-swilchedNd：YAGlaserasthefundamentalbeamsonreeatt．06a“nl。thegreenSHGat0．532Ⅱmwasobtainedfromperiodicallyp

7、oledMg：LNat1．亭％conversionefficiency．UsingaTi：sapphirelaser，third—orderquasi—phase·matchedsecondharmonicvioletlightgenerationWasdemonstratedinperiodicallypoledMg：SLN，withanenergyconversionefficiencyof20．5％．IIKeywords：Quasi-phase—matched(QPM)TheswitchingfieldSecondharmonicge

8、neration(SHG)PeriodicallypoledlithiumniobatedopedMgOPeriodicallypolednear-stoichiometricl