简介:线阵CCD已广泛应用于在线检测、图像识别等系统,目前高帧率采集系统多在200~500Hz之间。高速线阵CCD采集系统,如1K甚至10KHz以上的采集要求,设计难度大,电路实现复杂,需要专用处理器,产品成本高,提出了一种采用并行高速FPGA驱动线阵CCD,通过常规分立元件完成模拟信号处理,实现数字信号实时传输的方案。该方案不仅简化了硬件设计上的难度,在同等性能情况下,可实现每秒万帧的高速采样,大幅度降低了成本。方案选用AlteraFPGA作为控制核心,实现高速信号采集的同时,在片上实现一定的图像算法,不仅加速了图像处理速度,同时降低了计算机的处理压力。最后,本电路通过USB2.0接口,完成数据的实时传输。设计具有高帧率、高灵敏度、性能稳定,便携使用等特点,同时还有一定的通用性,已应用于一些光学系统中。
简介:Athree-dimensionalmodelofGaAs/A1GaAsquantumdoubleringsinthelateralstaticelectricfieldisinvestigatedtheoretically.Theeigenvalueproblemwiththeeffective-massapproximationissolvedbymeansofthefinite-elementmethod.Theenergylevelsandwavefunctionsofquantum-confinedelectronsandheavyholesareobtainedandshowanagreementwithourprevioustheoreticalandexperimentalstudies.ItisshownintheapproximationofneglectingtheCoulombattractionbetweentheelectronandheavyholethatarelativelylargeStarkshiftofexcitonemissionof4meVisattainablewithanappliedelectricfieldof0.7kV/cm.
简介:WecreateaGaNphotocathodebasedongradedAlxGa1-xNbufferlayerstoovercometheinfluenceofbuffer-emissionlayerinterfaceonthephotoemissionoftransmission-modeGaNphotocathodes.Agateshapedspectralresponsewitha260-nmstartingwavelengthanda375-nmcut-offwavelengthisobtained.Averagequantumefficiencyis15%andshortwavelengthresponsesarealmostequivalenttolongwavelengthones.Thefittedinterfacerecombinationvelocityis5×104cm/s,withnegligiblemagnitude,provingthatthedesignofthegradedbufferlayersisefficientinobtaininggoodinterfacequalitybetweenthebufferandtheemissionlayer.
简介:Asecondgenerationsolaradaptiveoptics(AO)systemisbuiltandinstalledatthe1-mNewVacuumSolarTelescope(NVST)oftheFuxianSolarObservatory(FSO)in2015.TheAOhigh-ordercorrectionsystemconsistsofa151-elementdeformablemirror(DM),acorrelatingShack–Hartmann(SH)wavefrontsensor(WFS)witha3500Hzframerate,andareal-timecontroller.ThesystemsawfirstlightonMar.16,2015.Thesimultaneoushigh-resolutionphotosphereandchromosphereimageswithAOareobtained.Theon-skyobservationalresultsshowthatthecontrastandresolutionoftheimagesareapparentlyimprovedafterthewavefrontcorrectionbyAO.
简介:Anall-fiberopticallaserpulsemulti-passstretcherusingachirpedfiberBragggrating(CFBG)isdemonstrated.Pulsesfroma1053-nmmode-lockedfiberseedoscillatorarestretchedbymultiplepassingthroughachirpedfibergratingsetinafiberregenerativeamplifierstructure.Westretchthepulsefrom16psto1.855nsafterittransmitssevenloopsinthestretcher.Themainfactorsthataffectthestretchingresultsarediscussed.
简介:SiO_2thinfilmscontainingSi_(1-x)Ge_xquantumdots(QDs)arepreparedbyionimplantationandannealingtreatment.Thephotoluminescence(PL)andmicrostructuralpropertiesofthinfilmsareinvestigated.ThesamplesexhibitstrongPLinthewavelengthrangeof400—470nmandrelativelyweakPLpeaksat730and780nmatroomtemperature.Blueshiftisfoundforthe400-nmPLpeak,andtheintensityincreasesinitiallyandthendecreaseswiththeincreaseofGe-dopingdose.Weproposethatthe400—470nmPLbandoriginatesfrommultipleluminescencecenters,andthe730-and780-nmPLpeaksareascribedtotheSi=OandGeOluminescencecenters.