简介:Inordertodeterminetheappropriatetreatmentinterval,267patientswhounderwent3sessionsoftreatmentwithQ-switchedalexandritelaserweredividedinto4groupsaccordingtotreatmentinterval,andtheirclinicalresponseswerecompared.Amongthem,187wereaskedabouttheprocessofpigmentfading.Moreover,lightandtransmissionelectronmicroscopywereperformed.Itwasnotedthattheclinicalresponseofthe5-6monthintervalgroupwassignificantlybetterthanthatofthe3-4monthgroup,butshowednosignificantdifferencefromthatofthe7-8or≥9monthgroup.80.21%ofinvestigatedpatientsstatedthatmarkedpigmentfadingcouldnolongerbeobserved7monthsafterirradiation.4monthsafterirradiation,thedegeneratedmelanosomesandcelldebriswerestillscatteredamongcollagenfibers,scavengedgraduallybymacrophage.Inconclusion,anappropriatetreatmentintervalis5-6months.
简介:ApassivelyQ-switchedNd3+:YAGlaserwithcornercubeistheoreticallyandexperimentallystudied.Weanalyzethepolarizationvariationincavityandsimulatethepeakpower,pulseenergyandpulsewidthchangedwiththerotationangleofcornercubenumerically.Anexperimentismadetoverifythetheoreticalresults.Withrotatingtheangleofcornercubeabouttheaxisthevariationrangeofpeakpoweris1.77MW(from10.36to8.59MW),andthatofpulseenergyis14.9mJ(from159.5to174.4mJ),thefluctuationofpulsewidthis2.95ns.Theexperimentalresultsagreewiththetheoreticalanalysistotheextentofvariationrules.Themostdynamictostaticenergyratioof62.5%isachieved.
简介:Diode-pumpedpassivelyQ-switchedNd:GdVO4/Cr4+:YAGlaserswithasimpleflat-flatcavityweredemonstrated.Themaximumaverageoutputpowerat1.06μmwas1.25W.Thehighestpeakpowerandpulseenergywere7.56kWand75μJ,respectively,withthepulserepetitionrateof11.1kHzandpulsewidthof10nsattheincidentpumppowerof8W.
简介:WedemonstratethegenerationofQ-switchedpulsesfromanytterbium-dopedfiberlaser(YDFL)usingquantumdot(QD)CdSeasapassivesaturableabsorber(SA).TheCdSeQDisfabricatedbythesynthesisofCdO,Se,andmanganeseacetateandparaffinoilandoleicacidasthesolventandsurfactant,respectively.TheCdSeQDisthendopedintopoly-methyl-methacrylate(PMMA)viaanemulsionpolymerizationprocess.APMMAhostedCdSeQDthinflakewithahomogeneousendsurfaceisthenformedandplacedbetweentwoferrulesandassembledinaYDFLcavitytoachievetheQ-switchingoperationwitharepetitionrateof24.45to40.50kHzwhilevaryingthepumppowerfrom975to1196mW.Thepulsewidthchangesfrom6.78to3.65μswithamaximumcalculatedpulseenergyat0.77μJatapumppowerof1101mW.ThisworkmaybethefirstdemonstrationofCdSeQD-basedQ-switchinginanall-fiberconfigurationthatshouldgiveproportionalinsightintosemiconductorQDmaterialsinphotonicsapplications.
简介:Adiode-end-pumpedelectro-optic(EO)Q-switchedgreenlaseroperatingattherepetitionrateof20kHzisreported.AblockofLa_3Ga_5SiO_(14)(LGS)singlecrystalisusedasaQ-switchandthetypeⅠphase-matchingLiB_3O_5(LBO)isusedasthenonlinearcrystalinthesecondharmonicgeneration.The2.3-Waveragepowerof532-nmgreenlaserisobtainedattherepetitionrateof20kHzwiththepulsewidthasshortas10ns.Whentheoutputpowerisabout1.5W,themeasuredpowerfluctuationislessthan1.4%(root-mean-square,RMS)withthebeamqualityfactorofM~2<2inbothorthogonaldirections.
简介:AQ-switcheddistributedBraggreflectorfiberlaserusingagraphenepassivesaturableabsorberisproposedinacavityconsistingofafiberBragggratingandFaradayrotatormirrorasendmirrors,togetherwithahighlydopederbium-dopedfiberasagainsource.ThelaserhasaQ-switchedthresholdofabout28mWandatunablerepetitionrateof10.4-18.0kHzwithvaryingpumppower.Theshortestpulsewidthobtainedfromthesystemis3.7μs,withamaximumpulseenergyandpeakpowerof22.2nJand3.4mW,respectively.
简介:Ahigh-repetition-rateeye-safeopticalparametricoscillator(OPO),usinganon-criticallyphase-matchedKTPcrystalintracavitypumpedbyapassivelyQ-switchedNd:GdVO_4/Cr~(4+):YAGlaser,isexperimentallydemonstrated.Theconversionefficiencyfortheaveragepoweris7%frompumpdiodeinputtoOPOsignaloutputandtheslopeefficiencyisupto10.3%.Withanincidentpumppowerof7.3W,thecompactintracavityOPO(IOPO)cavity,operatingat15kHz,producesanaveragepowerof0.57Wat1570nmwithapulsewidthasshortas6ns.Thepeakpowerat1570nmishigherthan6.3kW.
简介:在LD端面抽运的Nd:YVO4激光器中插入Cr^4+:YAG晶体,获得了稳定的1.06μm波长的高重复率被动调Q脉冲激光输出。实验研究了抽运功率、腔长、输出镜透过率对输出功率的影响,以及不同抽运功率下脉冲重复频率和脉冲宽度的变化,并对结果进行了理论分析。当腔长为8cm,抽运功率为27W时,得到重复率37.8kHz、平均功率3.5W的调Q脉冲序列;单个脉冲能量为93μJ、脉宽为24ns、峰值功率为3.9kW。
简介:Wereportonthecontinuous-wave(CW)andpassiveQ-switchingperformanceofaminiatureYb:Y3Ga5O12crystallaserendpumpedbya935-nmdiodelaser.AmaximumCWoutputpowerof12.03Wisproducedwithanoptical-to-opticalefficiencyof54.4%,whiletheslopeefficiencyis63%.InthepassivelyQ-switchedoperationachievedwithaCr4+:YAGsaturableabsorber,anaverageoutputpowerof2.12Wat1025.2nmisgeneratedwithaslopeefficiencyof46%atapulserepetitionrateof5.0kHz.Thepulse’senergy,duration,andpeakpowerare424μJ,2.3ns,and184.3kW,respectively.
简介:Wereportaline-narrowedelectro-opticperiodically-poled-lithium-niobate(PPLN)Q-switchedlaserwithintra-cavityopticalparametricoscillationusingagrazing-incidencegrating,producing8-ns,5-μJpulsesat10-kHzrepetitionratewhenpumpedwitha10-Wdiodelaserat808nm.Theoutputwavelengthiscenteredat1554.3nmwitha0.03-nmspectralwidth.Wavelengthtuningisachievedbyrotatingamirrorandchangingthecrystaltemperature.
简介:Adiode-end-pumpedelectro-optic(EO)Q-switchedNd:YVO4laseroperatingatrepetitionrateof10kpps(pulsespersecond)wasreported.AblockofLa3Ga5SiO14(LGS)singlecrystalwasusedasaQ-switchandthedriverwasametaloxidesemiconductorfieldeffecttransistor(MOS-FET)pulserofhighrepetitionrateandhighvoltage.Atcontinuouswave(CW)operation,theslopeefficiencyofthelaserwas46%,andmaximumoptical-to-opticalefficiencywas38.5%.Usinganoutputcouplerwithtransmissionof70%,a10-kppsQ-switchedpulsetrainwith0.4-mJmonopulseenergyand8.2-nspulsewidthwasachieved,theopticalconversionefficiencywasaround15%,andthebeamqualityM2factorwaslessthan1.2.
简介:机载光电侦察吊舱为各类侦察应用提供了数据保障,应用需求也从传统的可见光/红外目标跟踪、有源定位、地理跟踪、火炮校射发展到无源定位,并进一步拓展到辅助着舰/着陆、广域探测、多目标记忆跟踪、机器学习与目标智能识别、视觉辅助导航等多项应用领域,机载光电侦察吊舱已经成为了一种高度集成的目标深度侦察工具。对上述应用领域的相关技术现状和发展进行了归纳和总结,指出并分析了当前机载光电侦察吊舱综合信息处理技术领域存在的主要突出问题,包括海量数据与计算资源有限的矛盾、多传感器综合应用深度尚浅、综合信息的误差分析及仿真评估不充分,而未来综合信息处理技术应朝着智能化、标准化和工程化等方向发展,才能有效提高情报搜集和处理效率,进而充分挖掘出机载光电侦察吊舱的应用潜力。