简介：Theinfluenceofcircularapertureontheintensityofhigh-orderharmonicgeneration(HHG)withintensefemtosecondlaserpulsewasstudiedbothexperimentallyandtheoretically.TheintensityvarietyofHHGwiththediameterofcircularaperturewasobservedinpulsedArgas.TheresultwasdiscussedandinterpretedintermsofthetheoryofHankeltransform.ItisfoundthatusingtheGaussianbeamtruncatedbyanaperturecouldenhancetheconversionefficiencyofHHGatcertainconditions.

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简介：ResearchdemonstratesthataFresnelhologramcanbegeneratedandsimultaneouslyencryptednumericallybasedonasecretsymmetrickeyformedbythemaximallengthsequence(M-sequence).Themethodcanbedirectlyextendedtoencryptavideoholographicclipinaframe-by-framemanner.However,giventhelimitedcombinationofsignalsinthefamilyofM-sequence,hackingthesecretkeythroughtrialanderrorcanbetimeconsumingbutnotdifficult.Inthisletter,weproposeamethodthatisdifficulttocrackwithbruteforceforencryptingaholographicvideosequence.AnM-sequenceisfirstrandomlyassignedtoencrypteachframeoftheholographicvideosignal.Subsequently,theindexoftheselectedM-sequence,whichisnecessarytodecryptthehologram,isencryptedwiththeRSAalgorithmbeforetransmittingtothereceivingend.Atthereceivingend,thedecoderisprovidedwithaprivatekeytorecovertheindexforeachframe,andthecorrespondingM-sequenceisusedtodecrypttheencodedhologram.

简介：Wepresenttheall-fibersystemforsupercontiuum(SC)generationwithpicosecondpulses.Bylaunching1.6-pspulsesfrompulsederbium-dopedfiberlaser(EDFL)intoasectionofphotoniccrystalfiber(PCF),thespectralbroadeningisobserved.Thebandwidthof237nm(at20dBlevel)isachieved.

简介：TheenhancementofstimulatedRamanscattering(SRS)ofacetone(C3H6O)andthegenerationofthreecolorlasersinlasingdyerhodamineB(RB)werereported.Thefirst-orderStokeswave(629.9nm)ofSRSofC3H6Owasamplifiedby2.83timesthanthatofpureCsH6O.Atthesametime,adyelaserofRBatthewavelengthfrom575to598nmcanbegeneratedinasuitableconcentrationofRBbetween3×10-5and2×10-4mol/L.Thusthegreenpumplaser,yellowdyelaser,andredStokeswaveconcurred.

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简介：Wereportontherichdynamicsoftwo-dimensionalfundamentalsolitonscoupledandinteractingonthetopofanellipticalshapedpotentialinatwo-dimensionalGinzburg–Landaumodel.Undertheellipticalshapedpotential,thesolitonsdisplayuniqueanddynamicproperties,suchasthegenerationofstraight-linearrays,emissionofeitheroneellipticalshapedsolitonorseveralellipticalringsolitonarrays,andsolitondecay.Whenchangingthedepthandsharpnessoftheexternalpotentialandfixingotherparametersofthepotential,variousscenariosofsolitondynamicsarealsorevealed.Theseresultssuggestsomepossibleapplicationsforall-opticaldata-processingschemes,suchastheroutingoflightsignalsinopticalcommunicationdevices.

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：Weproposeanovelschemeforopticalfrequency-lockedmulti-carriergenerationbasedonadirectlymodulatedlaser(DML)andaphasemodulator(PM)incascadethroughsynchronoussinusoidalradiofrequency(RF)signal.TheoptimaloperatingzoneforthecascadedDMLandPMschemeisdeterminedviatheoreticalanalysisandnumericalsimulation.Wedemonstrate16opticalsubcarrierscanbesuccessfullygeneratedbasedonthecascadedDMLandPMschemeintheoptimalzone.Thegenerated16opticalsubcarrieshavefrequencyspacingof12.5GHzandpowerdi?erenceoflessthan3dB.Theseresultsagreewellwiththoseofthenumericalsimulation.Wealsodemonstrateintensitymodulationanddirectdetection(IM-DD)basedononeofthe16generatedopticalsubcarriers.After20-kmsingle-modefiber-28(SMF-28)transmission,thebit-errorratio(BER)of1×10-9canbeattainedforboth3.125-and12.5-Gb/sbitrates.

简介：AQ-switcheddistributedBraggreflectorfiberlaserusingagraphenepassivesaturableabsorberisproposedinacavityconsistingofafiberBragggratingandFaradayrotatormirrorasendmirrors,togetherwithahighlydopederbium-dopedfiberasagainsource.ThelaserhasaQ-switchedthresholdofabout28mWandatunablerepetitionrateof10.4-18.0kHzwithvaryingpumppower.Theshortestpulsewidthobtainedfromthesystemis3.7μs,withamaximumpulseenergyandpeakpowerof22.2nJand3.4mW,respectively.

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简介：Toobtainhighpower589-nmyellowlaser,aT-shapedthermal-insensitivecavityisdesigned.Theoptimalpowerratioof1064-and1319-nmbeamsisconsideredandthefundamentalspotsizedistributionfromtheoutputmirrortothetwolaserrodsarecalculatedandsimulated,respectively.Asaresult,a589-nmyellowlaserwiththeaverageoutputpowerof5.7Wisobtainedintheexperimentwhenthetotalpumpingpoweris695W.Theoptical-to-opticalconversionefficiencyfromthefundamentalwavestothesumfrequencygenerationisabout15.2%andthepulsewidthis150nsattherepetitionrateof18kHz.Theinstabilityoftheyellowlaserisalsomeasured,whichislessthan2%within3h.ThebeamqualityfactorsareM_x~2=4.96andM_v~2=5.08.