Cw Laser Power and Energy Calibrations

1 Page 1 NAT'LINSTOFSTAND&TECH A111D7DITDMD NI8T PUBL!CAT!0N8; NISTMeasurementServices: nist cwLaserPowerandEnergy o^uf^'* ^ ,a11^-^ Publication CalibrationsatNIST 250-75 JoshuaHadler Christopher L.Cromer JohnH.Lehman <3C ioo •^5... Open at page → 2 Page 2 rhe NationalInstituteofStandardsandTechnologywasestablishedin1988byCongressto"assistindustryinthe developmentoftechnology ...neededtoimproveproductquality,tomodernizemanufacturingprocesses,toensure productreliability ...... Open at page → 3 Page 3 NISTSpecialPublication250-75 NISTMeasurementServices: cwLaserPowerandEnergyCalibrationsatNIST JoshuaHadler Christopher L.Cromer JohnH.Lehman Optoelectronics Division ElectronicsandElectricalEngineeringLaboratory National... Open at page → 4 Page 4 Certaincommercialentities,equipment,ormaterialsmaybeidentifiedinthisdocument inordertodescribe anexperimentalprocedureorconceptadequately.Suchidentification isnotintendedtoimply recommendation orendorsementbytheNationalI... Open at page → 5 Page 5 Contents Page 1. Introduction 1 2. CalibrationServiceSummary 1 3. TheoryofMeasurement 2 3.1 SystemBasicsandMeasurementPrinciple 2 3.2 MeasurementEquations 3 3.3 DataAnalysis 4 4. MeasurementSystem 7 4.1 MeasurementStanda... Open at page → 7 Page 7 cwLaserPowerandEn&rgyCalibrationsatNIST JoshuaA.Hadler,ChristopherL.Cromer,andJohnH.Lehman NationalInstituteofStandardsandTechnology 325Broadway Boulder,Colorado80305 Thisdocumentdescribesacalibrationserviceforabsolutela... Open at page → 8 Page 8 deviceundertest(DUT),issenttoNIST,whereitisthencomparedtotheappropriatelaboratory standardusingacahbratedbeamspUttermeasurementsystem. TheDUTmaysimplybeastandalonedetector,oritmaybeanintegratedsystemwithan independentdis... Open at page → 9 Page 9 Twocalibrateddetectors(standards)areusedtocalibratetheDUTbysubstitutionoftheDUT foroneofthestandards.Awedgebeamsplitter ispositionedtodirectareflectedbeamtoone standardandthetransmittedbeamtoasecondstandard.Theopticalpro... Open at page → 10 Page 10 (3.2) ThevalueofthebeamspHtterratiocanbedeterminedbysimultaneouslymeasuringboththe transmittedandreflectedbeamsincidentonthestandarddetectors.Thisgivesusthebeamsplitter ratioRintermsofthelaserpowermeasuredbyeachstandard.... Open at page → 11 Page 11 ashutter-openperiod,duringwhichthelaserimpingesontheDUT.Laserpowermeters generallyhaveanoutputthatreachesanequilibriumvaluesometimeaftertheshutterisopened, whichiscalledthesettlingtime. Thedetector'ssetthngtimeisderivedf... Open at page → 12 Page 12 integratedfromthedataacquiredduringtheperioddefinedbytheopeningoftheshuttertothe endofthesetthngtimeaftertheshutterisclosed.Othertypesofenergymetersmayrequirea measurementofthepeakoutputfromtheDUTastheoutputtouseinthecaH... Open at page → 13 Page 13 4.MeasurementSystem 4.1MeasurementStandards Energyandpowermeasurementscanbeacquiredusingavarietyoftypesofdetectors.Such detectorsmightinclude,butarenotHmitedto,thermopiles(surfaceandvolumeabsorbers), calorimeters,anddiod... Open at page → 14 Page 14 4.3OpticalSetup Standard1 Tratulatian Stage 12 Eiclosijifi Slmtter Attenualnr EntranceIris ML'> Beamsplitter EnclosijM Figure4.3.Exampleopticallayout. ThebasicopticalsetupisrepresentedhereinFig.4.3. 4.3.1Attenuator Anatt... Open at page → 15 Page 15 measurementlabmayexperience.Eachenclosurecontainsitsownprecisionmeasurement electronicstoavoidunnecessarilylongsignalpathlengthstothedataacquisitionelectronics. Thesemetersarethenreadremotelyviacomputerintothedataacquisi... Open at page → 16 Page 16 5.StandardOperatingProcedures 5.7SystemStartup Allelectronicsandothersupportsystemsarepoweredupatleastonehourpriortothestartofthe measurement.Alltestequipmentisallowedtoequilibratewithroomtemperature.Thelaseris selectedf... Open at page → 17 Page 17 6.Setadjustableaperturesinthebeampathstoblockscatteredlightandstraybeams,but notsoastooccludethemeasuredbeam. 5.3DUTAlignment TheDUTismountedonatranslationstagesuchthatitcanbeeasilyinsertedandremovedfrom theincidentbeam.... Open at page → 18 Page 18 5.Standard/monitor gain. 6.Background,orratingperiod. 7.Injectiontime. 8.Settlingtime(usually7xtimeconstant).Thesettlingtimeisgenerallyestablishedbythe manufacturer's specification.Wherethesettlingtimeislessthanthatofthe... Open at page → 19 Page 19 6.UncertaintyEvaluation TheuncertaintyestimatesfortheNISTlaserpowerandenergymeasurementsareassessed followingguidelinesgiveninNISTTechnicalNote1297,"GuidelinesforEvaluatingand ExpressingtheUncertaintyofNISTMeasurementRes... Open at page → 20 Page 20 6.1.1SpectralResponsivity(TypeB) Spectralresponsivity isgenerallydefinedasoutputperincidentpowerand/orenergy.Itis expressedmostoftenasresponsivityataspecificwavelength,mostnotablyfordiode-based detectors,whichcanhavelarg... Open at page → 21 Page 21 thedetectorresponseasafunctionoftemperature.Anexampleofsuchbehaviorisdocumented inNISTSpecialPublication250-53[19]. 6.1.6WindowTransmittance(TypeB) Foradetectorwhereresponsivity isdeterminedbymethodsotherthandirectsubsti... Open at page → 22 Page 22 6.2MeasurementSystemUncertainties Theuncertaintiesforthisserviceareincludedineachcalibrationreport,andaresummarized here.Theerrorbudgetissummarizedbelowintable6.2. 6.2.1 InjectionTime(TypeB) Theevaluationofenergymetersan... Open at page → 23 Page 23 6.2.6TransferMeasurement(TypeA) Theaccuracyofthedirectsubstitutionmeasurement isquantifiedbythestandarddeviationof thetransfer-standard cahbrationfactors(seeEqs.3.4aand3.4b). Table6.2.Examplesummaryofsystemuncertaintie.y... Open at page → 24 Page 24 7.QualityControl TheOptoelectronicDivisionmeasurementservicesmakeuseofqualityassurancepracticesto ensurethevalidityofmeasurementresultsandtheiruncertainties.Suchpracticesinclude: •Repeatedmeasurements/calibrations compar... Open at page → 25 Page 25 9.Glossary Calorimetry: Themeasurementofthequantityofheatexchanged.Inthisservice,thecalorimeter isusedto quantifytheamountofthermalenergydepositedbyalasersource. DirectSubstitution: SubstitutingaknownstandardforaDUTinide... Open at page → 26 Page 26 Material;FusedSilica AngleofIncidence:-8,76° Scale: 6mm Figure9.1.Diagramofwedgebeamsplitter. StandardUncertainty: Therepresentationofeachcomponentcontributortotheuncertaintyofameasurement result. Typicallyexpressedwitht... Open at page → 27 Page 27 10.References [I]BarryN.Taylor,TheInternationalSystemofUnits(SI).NISTSpecialPublication330;2001. [2]BarryN.Taylor,GuidefortheuseoftheInternationalSystemofUnits(SI).NISTSpecial Publication811;1995. [3]XiaoyuLi,ThomasScott... Open at page → 28 Page 28 AppendixA.MeasurementSystemUncertainties A.lInjectionTime(TypeB) Anupperboundwasestablishedbasedontheshuttermanufacturer's specifications,whichare thefollowing: Shutter:Windowspeed=48ms ShutterController:±10%ofshutterspe... Open at page → 29 Page 29 A.3LaserPowerDrift Noisethatistermeddrift(or\lfnoise)iscommontoabroadrangeofphysicalsystemsandis observedatlowfrequencies(havingamagnitudeinverselyproportionaltofrequency). Itis typicallynotbasedonasinglephenomenon;rathe... Open at page → 30 Page 30 Modeled3%LaserPowerDriftOver200sInjectionPeriod FigureAl.Laserpowerdriftmodel. Reference [Al]D.W.Allan,Shouldtheclassicalvariancebeusedasabasicmeasureinstandardstechnology?IEEETrans. Instrum.Meas.IM-36:646-654;1987 24 Open at page → 31 Page 31 AppendixB.SampleCalibrationReport U.S.DEPARTMENTOFCOMMERCE NATIONALINSTITUTEOFSTANDARDSAND TECHNOLOGY ELECTRONICSANDELECTRICALENGINEERING LABORATORY Boulder,Colorado80305 ReportofCalibration(42110CA) LASERPOWERMETER <DUT... Open at page → 32 Page 32 LASERPOWERMETER DetectorModelNo: DisplayModelNo: Figure1.Measurementsetup. UncertaintyAssessment TheuncertaintyestimatesfortheNISTlaserenergymeasurementsareassessedfollowingguidelines giveninNISTTechnicalNote1297,"Guidel... Open at page → 33 Page 33 LASERPOWERMETER DetectorModelNo: DisplayModelNo: Sr = (Zx)^ N N-1 wherethexvaluesrepresenttheindividualmeasurementsandNisthenumberofxvaluesusedfora particularTypeAerrorcomponent.ThestandarddeviationofthemeanisSr/N'^,andt... Open at page → 34 Page 34 LASERPOWERMETER DetectorModelNo: DisplayModelNo: FortheDirector, NationalInstituteofStandardsandTechnology CalibratedBy: MariaL.Dowell,GroupLeader Sources,DetectorsandDisplaysGroup OptoelectronicsDivision JoshuaHadler,Ph... Open at page → 35 Page 35 TechnicalPublications Periodical JournalofResearchoftheNationalInstituteofStandardsandTechnology—ReportsNISTresearchand developmentinmetrologyandrelatedfieldsofphysicalscience,engineering,appliedmathematics, statistics,... Open at page → 36 Page 36 U.S.DepartmentofCommerce NationalBureauofStandardsandTechnology 325Broadway Boulder,CO80305-3328 OfficialBusiness PenaltyforPrivateUse$300 Open at page →