简介：Alow-thresholdRamaneffectinakilowattytterbium-dopednarrowbandfiberamplifiersystemisreported.TheRamanStokeslightat1120nmisachievedwiththetotaloutputpowerofonly~400W,indicatingthattheRamanthresholdofthiskilowattcodirectionalpumpedcontinuouswavefiberamplifierismuchlowerthanthepredictedvalueestimatedbytheclassicformula.Tofigureoutthemechanismofthisphenomenon,simulationsbasedonthegeneralstimulatedRamanscattering(SRS)modelareanalyzedindicatingthatthekeyfactoristhecouplingbetweenfour-wavemixing(FWM)andSRS.Thesimulationresultsareingoodagreementwithourexperiments.

简介：Alightpurplishredsapphireisheattreatedinanairtightcrucible.Thesamplechangeslittleincolorafterreceivingheattreatmentat1100°C,butturnstolightblueandblueafterbeingtreatedat1200°Cand1300°C,respectively.Beforeheating,theUV-VISabsorptionspectraofthesamplearedominatedbythe551nmbroadabsorptionbandcontributedbythed-electrontransition~4A_2→~4T_2ofCr~(3+).Afterheating,theUV-VISabsorptionspectraaredominatedbythe563nmbroadabsorptionbandcontributedbytheintervalencechargetransferofFe~(2+)-Ti~(4+).ThexrayphotoelectronspectroscopytestrevealsthattheFe~(2+)andTi~(4+)ioncontentsincreasewithincreasingtemperature.ThesapphirechangingfromlightpurplishredtoblueintheheatingprocessisowingtothefactthattheFe~(2+)andTi~(4+)contentsgrowandtheintervalencechargetransferofFe~(2+)-Ti~(4+)selectivelyabsorbsUV-VISlight.

简介：Theself-assembledInAs/GaAsquantumdots(QDs)withextremelylowdensityof8×10~6cm~(-1)areachievedusinghighergrowthtemperatureandlowerInAscoveragebylow-pressuremetal-organicchemicalvapourdeposition(MOVCD).Asaresultofmicro-photoluminescence(micro-PL),forextremelylowdensityof8×10~6cm~(-1)InAsQDsinthemicro-PLmeasurementsat10K,onlyoneemissionpeakhasbeenachieved.ItisbelievedthattheInAsQDshaveagoodpotentialtorealizesinglephotonsources.

简介：Withthedevelopmentofhighpowerultrafastlaserpassivelymode-lockedbyasemiconductorsaturableabsorbermirror(SESAM),thedamagethresholdanddegenerationmechanismoftheSESAMbecomemoreandmoreimportant.OnewaytoreducethemaximumelectricfieldinsidetheactivepartoftheSESAMistheuseofadielectriccoatingonthetopofthesemiconductorstructure.WithFresnelformula,opticaltransfermatrix,andopticalthinfilmtheory,theelectricfielddistributionandreflectancespectrumcanbesimulated.WeintroducethedesignprinciplesofSESAMincludingthedependenceofreflectancespec-trumondielectricfunctionofabsorber,andinvestigatethedependencesoftheelectricfielddistribution,modulationdepth,reflectancespectrum,andtherelativevalueofincidentlightpoweratthetopquantumwellofSESAMonthenumberofSiO_2/Ta_2O_5layers.

简介：Intense-laser-inducedabove-thresholdionizationofaboundelectronintocontinuumstateswithlowenergyisinvestigatedinthecontextofthestrong-fieldapproximationthatallowsforoneactofrescatteringoftherevisitingelectron.Thequantumorbitsforforwardandbackwardscatteringareevaluatedandgeneralizedtoarbitraryscatteringangles.Thevelocitymapoftheliberatedelectronexhibitsthewell-knownlow-energystructureaswellasotherfeaturesoffthepolarizationaxis.

简介：Inthiswork,wereportabroadbandterahertzwavemodulatorbasedonatop-gategraphenefieldeffecttransistorwithpolyimideasthegatedielectriconaPETsubstrate.ThetransmissionoftheterahertzwaveismodulatedbycontrollingtheFermilevelofgrapheneviathepolyimideasthetop-gatedielectricmaterialinsteadofthetraditionaldielectricmaterials.Itisfoundthattheterahertzmodulatorcanachieveamodulationdepthof~20.9%withasmalloperatinggatevoltageof3.5Vandalowinsertionlossof2.1dB.

简介：InthisLetter,wefocusonthetheoreticalanalysisoftherelativisticenergyandangulardistributionsoftheejectedphotoelectronsduringtherelativistictunnelionizationofatomsbyintense,circularlypolarizedlight.Wemakeasmallmodificationofthegeneralanalyticalexpressionsforthesedistributions.Theroleoftheinitialmomentum,theponderomotivepotential,andtheStarkshiftareconsidered.Wealsopresentthemaximalangleofelectronemission.

简介：Atunableslowlightof2.5-Gb/spseudo-randombinarysequencesignalusinga1550-nmvertical-cavitysurface-emittinglaser(VCSEL)isexperimentallydemonstrated.Theinfluencesofthebiascurrentandthegainsaturationontheslowlightareinvestigated.Withbiascurrentincreasing,tunableopticalgroupdelayupto98psisobtainedatroomtemperature.Demonstrationofthetimedelaybetween16and24psbysignalintensitychangeisreported.Underanappropriatebiascurrent,bytuningtheinputsignaltotrackthepeakgainwavelengthoftheVCSEL,slowlightofapowerpenaltyaslowas1dBisachieved.Withsuchalowpowerpenalty,theVCSELhasagreatpotentialapplicationasacompactopticalbuffer.

简介：

简介：Thisletterpresentsalowcostsolutionforwavelengthdivisionmultiplexedorthogonalfrequencydivisionmultiplexedpassiveopticalnetwork(WDM-OFDM-PON)withwidelytunableopticalfilterandlinearsmallform-factorpluggable(SFP)module.With9-nmtunablerangefrom1551to1560nm,thetunablefiltercansupportupto10-channel100-GHzspacingWDMPONsystem.Alinearavalanchephotodiode(APD)basedSFP+moduleisdesignedforopticalOFDMsignaldemodulation,whichcanprovidebetterreceiverperformancecomparedwithlimitingAPDmodule.Experimentalresultsshowthat～34dBpowerbudgetcanbeachievedin4×5-GbpsWDM-OFDM-PONsystem,whichcansatisfythetransmissionrequirementsofnextgenerationPONsystem.

简介：Squeezedstateoflightexploresanewerainnoiselesscommunicationanddataprocessingrecentlybreakingthequantumlimitofnoise.Weproposeanewmechanismofmodulatinganamplitude-squeezedsignalwiththeinstantaneousintensityvariationofacoherentsignal.Themodulatingsignalisacoherentlightwheretheamplitude-squeezedlighttakestheroleofacarriersignal.

简介：A100-Gb/shigh-speedopticaltransmitterisproposedandexperimentallydemonstrated.Basedonfrequency-quadruplingtechnique,twosub-channelswithafixed50-GHzspacingareobtainedfromonelasersource.Usingreturn-to-zerodifferentialquadraturephase-shiftkeying(RZ-DQPSK)modulationformatandpolarizationmultiplexing(PolMux),onlylow-speedelectronicdevicesof12.5GHzareneededforthe100-Gb/stransmitter.Thiseliminatestheneedofultrahigh-speedoptoelectronicdevicesandthusgreatlyreducesthecost.Theexperimentalresultsshowthatthistransmittercanachievegoodperfor-manceindispersiontoleranceofa25-kmsinglemodefiber(SMF).

简介：从理论上分析了玻璃微珠定向回归反射原理，利用近轴光线球面折射理论分析了玻璃微珠实现回归反射的折射率，并结合实际使用情况，在最大可能增加回归反射的基础上，讨论了入射光线到主光轴的距离与回归光线和入射光线夹角之间的关系，从而确定出了实现最大反射时玻璃微珠的折射率范围为1．80～1．95，研究结果对回归反射标志牌的开发具有重要的理论意义。

简介：利用单色平行光照射玻璃微珠,入射光在玻璃微珠内经过一次或多次内反射后出射光在最小偏向角会形成彩虹条纹。基于几何光学理论,根据最小偏向角的大小计算玻璃微珠的折射率。为了实现其快速测量,采用参数递推公式计算Otsu法的最佳阈值,并用改进的Otsu法对彩虹图进行了有效的阈值分割。提出了一种能快速有效判断彩虹条纹边缘的方法,并用该方法自动测量了彩虹条纹最外环边缘半径,从而实现了最小偏向角的快速计算。此外,对玻璃微珠折射率测量过程中的不确定度进行了计算,对不同型号的玻璃微珠,折射率的不确定度在10-4数量级,验证了上述方法的正确性。

简介：

简介：气泡是常见的玻璃缺陷,远场干涉法可直接测量玻璃厚度方向的气泡尺寸,为了给测量时观察角的选择提供理论依据,基于几何光学原理和菲涅尔公式,建立了光束的远场干涉模型并导出干涉条纹的相对光强计算公式。以冕牌玻璃（K6）、重冕玻璃（ZK6）、重火石玻璃（ZF6）为例,通过数值分析,得到干涉条纹的相对光强分布规律：相对光强幅度随折射率的增大而增大;全局来看,相对光强幅度随偏向角的增大呈先增大后减小的趋势,其变化不具有周期性;局部来看,相对光强幅值、条纹角间距近似相等,其变化具有近似周期性,且条纹的可见度较高。

简介：硫属玻璃是具有优良红外透过性质的光学材料。为了便于硫属玻璃系统的研究和设计，采用现有的玻璃性质计算理论，运用Delphi语言编程设计实现了硫属玻璃的物理性质计算及配方设计程序。

简介：提出了一种用于石英玻璃管壁厚非接触测量的光电检测技术，研制了石英玻璃管壁厚在线检测系统。在确定检测总体方案的基础上，进行了石英玻璃管厚度检测原理、发射光学系统、CCD器件选择和数据处理系统的研究。根据几何光学中反射与折射定律，利用三角关系建立了石英玻璃管壁厚和光束宽度之间的关系。对实验结果进行了误差分析，验证了方案的可行性，系统测量精度优于±0．01mm。系统调试和实际测量结果表明，研制的系统满足在线非接触测量要求。

简介：利用有限元法对脉冲CO2激光辐照K9玻璃样品中的温度和应力分布进行了数值分析。对半径为20mm、厚为2mm的圆盘样品的计算结果表明，K9玻璃的损伤由环向应力控制，体损伤先于面损伤产生，且光斑半径和脉冲数目对损伤闽值有较大的影响，在激光光斑半径为5mm，脉宽为10肛s的条件下K9玻璃的单脉冲CO2激光的损伤闽值为0．5J，相应的能量密度为0．637J／cm^2。损伤闽值随光斑半径的增大而增大，随脉冲数目的增加而变小。讨论了样品半径和厚度对损伤结果的影响，结果表明样品半径在10-20mm范围内所产生的拉伸应力较小。

简介：从传统光学冷加工的原理出发，分析了传统接触式加工方法中抛光剂与材料去除深度的理论关系，设计了微晶玻璃超光滑抛光过程中的抛光剂选型试验。通过比较基片的表面质量，摸索出适合微晶玻璃超光滑抛光的最佳抛光剂为金刚石微粉，成功加工出了超光滑微晶光学元件，其表面粗糙度达到0．2nm。