简介：

简介：Theenergytransmissionofthelongmicrowavepulseforthefrequencyof2.45GHzand5.8GHzisstudiedbyusingtheelectronfluidmodel,wheretheratecoefficientsarededucedfromtheBoltzmannequationsolvernamedBOLSIG+.Thebreakdownthresholdsfordifferentairpressuresandincidentpulseparametersarepredicted,whichshowgoodagreementwiththeexperimentaldata.Belowthebreakdownthreshold,thetransmittedpulseenergyisproportionaltothesquareoftheincidentelectricfieldamplitude.Whentheincidentelectricfieldamplitudehigherthanthebreakdownthresholdincreases,thetransmittedpulseenergydecreasesmonotonouslyatahighairpressure,whileatalowairpressureitfirstdecreasesandthenincreases.Wealsocomparethepulseenergytransmissionforthefrequencyof2.45GHzwiththecaseof5.8GHz.

简介：Muonsproducedbyashortpulselasercanserveasanewtypeofmuonsourcehavingpotentialadvantagesofhighintensity,smallsourceemittance,shortpulsedurationandlowcost.Tovalidateitinexperiments,asuitablemuondiagnosticssystemisneededsincehighmuonfluxgeneratedbyashortpulselasershotisalwaysaccompaniedbyhighradiationbackground,whichisquitedifferentfromcasesingeneralmuonresearches.Adetectionsystemisproposedtodistinguishmuonsignalsfromradiationbackgroundbymeasuringthemuonlifetime.Itisbasedonthescintillatordetectorwithwaterandleadshields,inwhichwaterisusedtoadjustenergiesofmuonsstoppedinthescintillatorandleadtoagainstradiationbackground.AGeant4simulationontheperformanceofthedetectionsystemshowsthatefficiencyupto52%couldbearrivedforlow-energymuonsaround200MeVandthisefficiencydecreasesto14%forhigh-energymuonsabove1000MeV.Thesimulationalsoshowsthatthemuonlifetimecanbederivedproperlybymeasuringattenuationofthescintillalightofelectronsfrommuondecaysinsidethescintillatordetector.

简介：Wereportonthedesignandperformanceofafiberlasersystemwithadaptiveacousto-opticmacropulsecontrolforanovelphotocathodelaserdriverwith3Dellipsoidalpulseshaping.Thelasersystemincorporatesathreestagefiberamplifierwithanintegratedacousto-opticalmodulator.Adigitalelectroniccontrolsystemwithfeedbackcombinesthefunctionsofthearbitrarymicropulseselectionandmodulationresultinginmacropulseenvelopeprofiling.Asabenefit,anarrowtemporaltransparencywindowofthemodulator,comparabletoalaserpulserepetitionperiod,effectivelyimprovestemporalcontrast.Inexperiments,wedemonstratedrectangularlaserpulsetrainprofilingattheoutputofathree-cascadeYb-dopedfiberamplifier.

简介：Thomsonscatteringimaging（TSI）isproposedandexperimentallydemonstratedtoobservethefinestructureofthelaserwakefield.ByThomsonscatteringaco-propagatinglaserpulse,weobtainc/earimagesindicatingthatthewakefieldislikeanacalephswimmingbehindthepumplaser.Thewavelengthofthewakefieldobservedatdifferentelectrondensitiesagreeswellwiththetheory.Sincenomathematicstransformationisinvolved,TSIcouldbepotentiallyusedasanonlinemonitorforfuture＇tabletop＇plasmaaccelerators.

简介：TheLaboratoryforIntenseLasers（L2I）isaresearchcentreinopticsandlasersdedicatedtoexperimentalresearchinhighintensitylaserscienceandtechnologyandlaserplasmainteraction.Currentlythelaboratoryisundergoinganupgradewiththegoalofincreasingtheversatilityofthelasersystemsavailabletotheusers,aswellasincreasingthepulserepetitionrate.Inthispaperwereviewthecurrentstatusofthelaserresearchanddevelopmentprogrammeofthisfacility,namelytheupgradedcapabilityandtherecentprogresstowardstheinstallationofanultrashort,diode-pumpedOPCPAlasersystem.

简介：

简介：Theexistingabsorptioncoefficientmeasurementinawatertubeislimitedinlowfrequencyduetothelimitationofthepulsetubelength.Awide-bandpulsetubemethodbasedonthepost-processinginversefilterisproposed.Afterobtainingtheresponseoftheentiresystem,thetransducerisexcitedwithwide-band,short-durationsignals.Then,thereceivedsignalsareprocessedwithinversefiltersandthe'blurred'reflectivesignalsofstandardreflectorandtestsamplearerecoveredrespectively,finally,thereflectioncoefficientandabsorptioncoefficientarecalculated.Simulationworkisimplementedtoverifytheadvantageofpostprocessinginversefilteroverpre-processinginversefilterintermsoflowfrequencymeasurement.Toverifytheproposedmethod,twodifferentwide-bandpulsesintheseparatefrequencyrangesareadoptedtomeasurethesamerubbermaterial.Theexperimentalresultsindicatethatthewide-bandpulsemethodandCW(ContinuousWave)pulsemethodhavegoodagreementinbothlowfrequencyrangeandhighfrequencyrange.Wide-bandpulsemethodisofhighefficiency,andthelowfrequencyreaches350Hz,whichisabletoextendthelowfrequencyrange.

简介：ThisLetterreportstheformationofperiodicsurfacestructuresonNi–Fefilmirradiatedbyasinglefemtosecondlaserpulse.Aconcavelenswithafocuslengthof-150mmisplacedinfrontofanobjective(100×,NA=0.9),whichtransformstheGaussianlaserfieldintoaringdistributionbytheFresneldiffraction.Periodicripplesformontheablationareaaftertheirradiationofasinglefemtosecondlaserpulse,whichdependsonthelaserpolarizationandlaserfluence.Weproposethattheringstructureofthelaserfieldleadstoasimilartransientdistributionofthepermittivityonthesamplesurface,whichfurtherlaunchesthesurfaceplasmonpolaritons.Theinteractionoftheincidentlaserwithsurfaceplasmonpolaritonsdominatestheformationofperiodicsurfacestructures.

简介：Pulse-pairs(PP)generatedbydistancemeasuringequipment(DME)causesevereinterferencetotheL-banddigitalaeronauticalcommunicationsystems.UnlikepreviousworksthatmainlyimprovedreceiverstructureformitigatingtheDMEinterference,thispaperproposesanovelandpracticaltimedomainPPmitigationmethodwithoutchangingtheexistingreceiverstructure.Ourmethodiscomposedofthreepartsandutilizesaspecificproperty,i.e.,arelativelyfixedwaveformofDMEPP.First,thecomplex-valuedwaveformofPPisautomaticallydetectedthroughaniterativeweightedaveragemethod.Then,onthebasisofthedetectedPPwaveform,eachPPisreconstructedaccordingtoitsamplitude,position,andinitialphase,whichareestimatedthroughasparserepresentationalgorithm.Finally,thereconstructedPPsaresubtractedfromthecontaminatedsignal.Numericalexperimentsshowthatcomparedwithrecentlypublishedmethodsthebiterrorrateobtainedbyourmethodisapproximately5dBbetter,whilethecomplexityismaintainedatthesamelevel.

简介：Nyquistfoldingreceiver(NYFR)isatypicalwidebandanalog-to-informationarchitecture.Focusingonthenoncooperativereceiving,thepulseradarsignalinterceptedbytheNYFRintimedomainisanalyzed.TheNYFRoutputsunderdifferentinputconditionsareinvestigatedbasedontheextendedFouriertransform(EFT)andthesamplingtheorem.CombiningwiththecharacteristicoftheNYFRoutputintimedomain,anewtimeofarrival(TOA)estimationmethodbasedontheenergyenvelopeandthewavelettransformisproposed.Theproposedestimationmethodcanbeadaptedforthenon-cooperativesituation.Ithasnorequirementforpriorinformationtodeterminethethresholdandisnotnecessarytotransformthesignalintobaseband.SimulationresultsprovethecorrectnessoftheNYFRoutputexpressionsandshowtheefficacyoftheproposedestimationmethod.

简介：TheapplicationofGolaypulsecodingtechniqueinspontaneousBrillouin-baseddistributedtemperaturesensorbasedonself-heterodynedetectionofRayleighandBrillouinscatteringistheoreticallyandexperimentallyanalyzed.Theenhancementofsystemsignaltonoiseratio(SNR)andreductionoftemperaturemeasurementerrorprovidedbycodingarecharacterized.Byusing16-bitGolaycoding,SNRcanbeimprovedbyabout2.77dB,andtemperaturemeasurementerrorofthe100mheatedfiberisreducedfrom1.4°Cto0.5°Cwithaspatialresolutionof13m.Theresultsarebelievedtobebeneficialfortheperformanceimprovementofself-heterodynedetectionBrillouinopticaltimedomainreflectometer.

简介：Brief-pulsestimulationat50Hzhasbeenshowntoterminateafterdischargesobservedinepilepsypatients.However,theoptimalpulsestimulationparametersforterminatingcorticalelectricalstimulation-inducedafterdischargesremainunclear.Inthepresentstudy,weexaminedtheeffectsofdifferentbrief-pulsestimulationfrequencies(5,50and100Hz)oncorticalelectricalstimulation-inducedafterdischargesin10patientswithrefractoryepilepsy.Resultsdemonstratedthatbrief-pulsestimulationcouldterminatecorticalelectricalstimulation-inducedafterdischargesinrefractoryepilepsypatients.Inconclusion,(1)abrief-pulsestimulationwasmoreeffectivewhentheafterdischargedidnotextendtothesurroundingbrainarea.(2)Ahigherbrief-pulsestimulationfrequency(especially100Hz)wasmorelikelytoterminateanafterdischarge.(3)Alowcurrentintensityofbrief-pulsestimulationwasmorelikelytoterminateanafterdischarge.

简介：Neutronusuallyappearswithgamma,whichisrequiringthedetectorhasthecapabilityofngammadiscrimination.Pulseshapediscrimination(PSD)isacommonapproachofn,gammajudgment,butrequiredacomplexprocesstoselectasuitablediscriminationfactor,andpoorperformanceinthelowenergyrange.AmethodbasedonthetimeintervalofadjacentSignalswasdisruptedandadoptedtocomparetopulseshapediscriminationinthefastneutrondetectionmethod.AgoodagreementbetweentheadoptedmethodandPSDmethodwasachieved,includingthetotalcountratioandneutroncountratio.Thecomparisonprovesthecorrectnessofthetheoreticalderivationandvalidatesthemethodinpractice.TheadvantagesandlimitationsofthemethodbasedontimeIntervalofadjacentsignalswereanalyzed.Themethodprovidesaneffectivewaytoconfirmthecalibrationoftheneutrondetectionofaliquidscintillationdetector.Also,asasimplewayonlyrequiringthetimeinformationaboutevents,thedescribedmethodhaslargeapplicationpotentialinsomecaseoffastneutronfluxorintensitymeasurement.

简介：Bysimultaneouslyemployingbothanelectro-opticmodulatorandcarbonnanotubesaturableabsorber（CNT-SA）inadual-lossmodulator,asubnanosecondsinglemode-lockingpulseunderneathaQ-switchedenvelopewithhighpeakpowerwasgeneratedfromadoublyQ-switchedandmode-locked（QML）Nd:Lu0.15Y0.85VO4laserat1.06μmforthefirsttime,toourknowledge.CNTswithdifferentwallstructures—single-walledCNTs（SWCNTs）,double-walledCNTs（DWCNTs）,andmulti-walledCNTs（MWCNTs）—wereusedasSAsintheexperimenttoinvestigatethesinglemode-lockingpulsecharacteristics.Atpumppowerof10.72W,themaximumpeakpowerof1.312MWwasobtainedwiththeDWCNT.