Spectroradiometric Detector Measurements Infrared Detectors

1 Page 1 NISTMeasurementServices: lAT'LINST.OFSTAND&TECHR.I.C. NIST fiEPERENCF ^1 IP PUBLICATIONS Spectroraaiometric DetectorMeasurements: PartIll-InfraredDetectors NIST Special Publication 250-42 AlanL.MigdallandGeorgeP.Eppeldau... Open at page → 2 Page 2 fhe NationalInstituteofStandardsandTechnologywasestablished in1988byCongressto"assistindustryin thedevelopnnentoftechnology . . .neededtoimproveproductquality,tomodernizemanufacturingprocesses,to ensureproductreliability... Open at page → 3 Page 3 NISTSpecialPublication250-42 NISTMEASUREMENTSERVICES: Spectroradiometric DetectorMeasurements: PartIll-InfraredDetectors AlanL.MigdallandGeorgeP.Eppeldauer OpticalTechnologyDivision PhysicsLaboratory NationalInstituteofS... Open at page → 4 Page 4 NationalInstituteofStandardsandTechnologySpecialPublication250-42 Natl.Inst.Stand.Technol.spec.Publ.250-42,59pages(Dec.1998) CODEN:NSPUE2 U.S.GOVERNMENTPRINTINGOFFICE WASHINGTON: 1998 ForsalebytheSuperintendent ofDocumen... Open at page → 5 Page 5 Preface ThecalibrationandrelatedmeasurementservicesoftheNationalInstituteofStandardsand Technology(NIST)areintendedtoassistthemakersandusersofprecisionmeasuring instrumentsinachievingthehighestpossiblelevelsofaccuracy,qu... Open at page → 6 Page 6 AbstractandKeyWords TheNationalInstituteofStandardsandTechnology(NIST)suppliescalibrationsofIR photodetector's spectralradiantpowerresponsivityfrom1.8|Limto20^im.Thespectral responsivityofadetectorundertestisdeterminedby... Open at page → 7 Page 7 TableofContents 1.INTRODUCTION 1 2.NISTSPECTRORADIOMETRIC DETECTORMEASUREMENT SERVICE 3 2.1DescriptionofMeasurementServices 3 2.2MeasurementLimitations 3 2.3HowToOrderSpecialTests 4 2.4TechnicalContacts 4 3.MEASUREMENTTH... Open at page → 8 Page 8 5.EQUIPMENTCHARACTERIZATIONS 15 5.1Alignment 15 5.2Sources 15 5.2.1ArgonMaxi-arc 15 5.2.2Quartz-HalogenTungstenFilamentLamp 15 5.3Monochromator 15 5.3.1RelayOptics 15 5.3.2SpatialApparatusFunction 17 5.3.3BeamUniformity... Open at page → 9 Page 9 6.SPECTRALRADIANTPOWERRESPONSIVITYSCALEREALIZATION 33 6.1BolometerResponsivityScale 33 6.LIRelativeSpectralResponsivity 33 6.LLlBolometerSpectralAbsorptance 33 6.L1.2BolometerWindowSpectralTransmittance 34 6.L1.3Relative... Open at page → 10 Page 10 ListofFigures Figure3.1Blockdiagramofphotodetectorsubstitutionmethod. 6 Figure4.1ERSCFoveralllayout.MindicatesoffaxisparobolicmirrorandMUXindicatesamultiplexer. 9 Figure4.2Theblockdiagramofthebolometerelectronics. 12 Fig... Open at page → 11 Page 11 Figure6.9Ratiooftheabsolutebolometerradiantpowerresponsivitytothescaledrelativeresponsivity.Theerror barsindicatethetotaluncertaintyoftheratios,onlytheerrorbarcapsareshownforclarity.Thesolidlineis thefittoaline. 44 Figur... Open at page → 13 Page 13 1. Introduction ThisdocumentdescribesanewNISTMeasurement Serviceforprovidingspecialtestsof infrared(IR)detectorssenttoNIST.Themainfocusofthisserviceistoprovidemeasurements ofabsolutespectralresponsivity(ASR)inthespectral... Open at page → 14 Page 14 Spatialresponsivityuniformityoveragivenareacanalsobequitepoor;variationsofhundreds ofpercenthavebeenseen.SpectralresponsivityvariationisaproblemintheIR,inpartbecause thatregionofthespectrumcoverssuchawiderange.Theusualwa... Open at page → 15 Page 15 2. NISTSpectroradiometric DetectorMeasurementService 2.1 DescriptionofMeasurementServices ThepresentcapabilitiesforIRphotodetector spectralpowerresponsivitymeasurementscover therangefrom1.8\imto20fim.Thedetectorscalerela... Open at page → 16 Page 16 2.3HowToOrderSpecialTests 1)ReferencetheServiceIDNumberonthepurchaseorder. DetailsofserviceIDnumber39090Sshouldbediscussedwithoneofthetechnicalcontacts listedinsec.2.3priortosubmittingaformalrequest. 2)Thepurchaseordersh... Open at page → 17 Page 17 TechnicalinformationcanalsobefoundatthefollowingInternetURL: http://physics.nist.gov/Divisions/Div844/facilities/phdet/phdet.html 3. MeasurementTheory Thegeneralmeasurementmethod,themeasurementequation,therealizationofth... Open at page → 18 Page 18 3.1.2DetectorSubstitution Detectorresponsivitymeasurementsbysubstitutioncanbemadeusingeq(4)andthefollowing equipment:abroadbandsource,monochromator, focusingoptics,andstandarddetector.(See fig.3.1.)Theradiantflux(power)0... Open at page → 19 Page 19 3.2.1Approximations Theassumptionsmadeinthedevelopmentofthemeasurementequationaresummarizedas follows.Thedevelopmentofthemeasurementequation,whichfollowedtheproceduredescribed inChapter5oftheSelf-StudyManualonOpticalRadi... Open at page → 20 Page 20 viaimagingoptics).Thislimitstheamountofflux(power)thatcanbedeliveredtothedetector andcanlimitsomeofthemeasurement possibilities. Deviationsfromthisapproximationcanbe consideredasanuncertaintyterm. Anotherassumptionaboutt... Open at page → 21 Page 21 Figure4.1 IRSCFoveralllayout.MindicatesamirrorandMUXindicatesa multiplexer. 4.1.2DescriptionofSources 4.1.2.1ArMaxi-arc TheIRSCFgenerallyusesaNISTdesignedargonmaxi-arcasitssource.Theargonmaxi-arc wasoriginallydevelopedas... Open at page → 22 Page 22 4.1.2.2QuartzLamp AGilway*partnumberL7390,100Wcurrentcontrolledquartz-halogenlampcanalsobeused asanIRsourceforthemonochromator. Thislampistypicallyusedforthenearinfraredendof thespectralrangewheremaximumspectralpowerisno... Open at page → 23 Page 23 Themonochromatorhasentranceandexitaperturesfrom0.4mmto2.0mmtosetthebeamspot size.Thebeamisimagedatf/Aontothedetector. 4.1.4OpticalRelaySystemandAssociatedHardware AschematicdiagramoftheopticsfortheIRSCFisshowninFigure4.1... Open at page → 24 Page 24 4.1.5TransferandWorkingStandards 4.1.5.1CryogenicBolometerStandard TheprimarytransferstandardfortheIRSCFisacompositecryogenicbolometeroperatednear 4K.Thebolometerconsistsofasapphirediskwithanabsorptivecoatingononesideand... Open at page → 25 Page 25 4.1.5.2InSbWorkingStandards PhotovoltaicInSbdetectorsareusedasworkingstandardsforthe2\imto5.4^imwavelength region.Thediameteroftheactiveareais4mmwitha3.5mmprecisionaperturemounted within 1mmofthedetectorsurface.Thedetect... Open at page → 26 Page 26 Duetolongdctimeconstants,bestresultsareobtainedbywaiting50sbetweenbiascurrent switchingandrecordingofthedcvoltage.Thisdcmeasurement isnotperformedforevery opticalmeasurementbecauseofthelongtimerequiredforthedcmeasurement... Open at page → 27 Page 27 inputlineisnotconnected,thespeedcanbecontrolledmanuallybyaknobonthefrontpanel. ThetwoshuttersareoperatedinparallelbyasingledriverwhichiscontrolledbyadigitalI/O linefromthecomputer. 5. EquipmentCharacterizations 5.1Alignm... Open at page → 28 Page 28 Theinputopticsconsistingofonesphericalandtwofoldmirrorsarejustusedtoimageasmuch ofthesourceradiationintotheinputapertureaspossible.Scattereffectsatthispointwerenot measuredbecausethisisunchoppedradiationandthuswouldnotaf... Open at page → 29 Page 29 5.3.2 SpatialApparatusFunction ThespatialapparatusfunctionwasmeasuredbyscanningaGedetector,coveredbyanaperture witha200|impinhole,acrossthenominal 1mmimageofthespectrometeroutputaperture. ThismeasurementwasdoneintheVIS/N... Open at page → 30 Page 30 knownwavelengthlaserlines.Thesmallmeasuredshiftsarefittoalinearfunctionwhichis addedtothegratingfunction. Generallythe3.39|imand10.6|amlasersareusedforthis purpose.Thiscorrectiontakesintoaccountslightmachiningorpositioni... Open at page → 31 Page 31 Figure5.3 Prismcalibrationcurve.Theposition(inencoder-driver steps)of peakprismtransmittance versuswavelength. Thespectralrangesofthe3 gratingsarealsoindicated. 5.3.5SpectralCharacterization Theslitscatterfunctionwasmeas... Open at page → 32 Page 32 Table5.1 Summaryofmonochromator spectralwidthsobservedusinglaser sources. Entriesfollowedby{12)indicatemeasurementsmadeusing2mm entranceandexitapertures.Allotherentriesweremadewith1mmapertures. Wavelength[M-ml 0.633 3.39... Open at page → 33 Page 33 efficiency,andspectrometerefficiency.Thesemeasurementsonlygivethe2ndorderrejections forthespecificwavelengthsmeasured,otherwavelengths willnotnecessarilyhavethesame rejectionlevels.Toquantifythesizeofthiseffectondetector... Open at page → 34 Page 34 5.4.2Lock-inGainRangeCalibration Thelock-ingainrangesof100mV,10mV,1mVand0.1mVwerecalibratedelectricallyand referencedtothe1Vrange.Thesefactors C]o^j^j^_g^ij,(G,^j^„)giveninTable5.2aremultipliedby themeasuredvoltagetogive... Open at page → 35 Page 35 Rif) = R(dc) [7] where f^^^ isthe3dBroll-offpoint.Toconvertfromtheobservedacsignaltothedcequivalent levelthecorrectionfactor whereA/j^gandA/aretheuncertaintiesofthebolometer3dBfrequencypointandtheoptical chopperfrequency... Open at page → 36 Page 36 T 1 1 1 1 r 120 Time[h] Figure5.5Changeof3dBroll-offfrequencywithtime.Thelineindicatesthe linearfittothedata. 5.5.1.3Responsivityvs.Temperature Theresponsivityofthebolometerdependsonitsquiescenttemperature.Becauseanumber... Open at page → 37 Page 37 2 C,^ M-(V,-V,(cal)) ' [in K.(cal) whereAM,Al/,,andAy„m(cal) aretheuncertaintiesofM, and^^^^(cal),respectively.For furtherdiscussionofthiscorrection,seeEppeldauer,etal.[EMG95]. 5.5.1.4Responsivityvs.BiasVoltage Thebolome... Open at page → 38 Page 38 n,=0.0231-0.01237V, =0.000909-0.0005246 , [13] withuncertaintiesofAn^=0.001and =0.00005.Althoughthenonlinearityalsodependson Vj,itrangesupto=10%at=10|iW.ValuesofC^^,asdeterminedbythesefitparameters versusFareshownforseve... Open at page → 39 Page 39 5.5.1.7SpatialResponsivity Thespatialvariationofthebolometerwasmeasuredbyscanningthebolometeracrossthe imagedoutputofthemonochromator.AnexampleofaspatialscanisshowninFigure5.7, indicatinga2.3mmregionwheretheresponsivity... Open at page → 40 Page 40 5.5.1.9BolometerGainRangeCalibration ThegaincalibrationofthebolometeramplifierwasmeasuredandisshowninTable5.3 referencedtogain100,themostcommonlyusedbolometergain. Table5.3 Bolometeracamplifiergaincalibrationreferencedto... Open at page → 41 Page 41 Time[h] Figure5.8 EffectofBolometerCorrectionProcedure. 5.5.2InSbWorkingStandards 5.5.2.1Responsivityvs.Time A0.25%responsivitychangewasmeasuredduringthe15.5hlongholdtimeofthedewar(see Figure5.9).Thisholdtimedependsonthe... Open at page → 42 Page 42 5.5.2.2Responsivityvs.Frequency Thecurrentpreamplifierswereoptimizedforachoppingfrequencyof40Hz.Fullandpartial frequencycompensationswereusedforthedifferentgains.Asaresult,the3dBroll-offpoints ofthedifferentsignalgainswe... Open at page → 43 Page 43 (0 c o a (/} o o N E 1.04 1.02 1 0.98 0.96 -|— I—r~i~r~ 1 ' '^ 10" i 10'^ 10" Power[W] 10 -3 Figure5.11 RatiosofInSbtoGeresponsivity(foridenticalradiantpower inputs)dividedbyaconstanttoyieldameanvaluenearunity. Therespon... Open at page → 44 Page 44 Wavelength[pm] Figure5.12Noiseandbackgroundcurrentvs.monochromatorwavelength. Themaximumdetectorcurrentcanbemeasuredatagainof10^V/A.A0.1mAmaximum currentonthe10Vfullscaleoutputvoltagecorresponds toamaximummeasurableradia... Open at page → 45 Page 45 a o N n E o <u in c o Q. in 0) CC (0 c 1.1 1.0 0.9 0.8 0.7 1 1 , 1 1 COS(a) - . \ Response 1 1 1 -3-2-10 1 2 3 Horizontal Position(mm) (a) -10 -5 0 5 10 IncidenceAnglea[°] (b) Figure5.13a)InSbhorizontalspatialresponsivit... Open at page → 46 Page 46 0) DC 0.10 0) o o 0 0.00 0.05 TotalDiffuseBolometerReflectance Reflectance Mean 0.00749 Std.Dev. 0.020 5 10 15 Wavelength [|jm] 20 Figure6.1 Thesolidcurveshowsthebolometergoldblackreflectance measuredusingaFTIRspectromet... Open at page → 47 Page 47 0.92 CD O C (0 0.91 E (0 c CD 0.90 0.89 (a) 0) o c (0 E 0) c CO (b) KBrtransmittance byIRSCF errorbarsarestd.dev.of5to9pts. 8 12 16 Wavelength (|jm) TransmittanceoftwoKBrwindows 20 0.91 0.9 0.89 2-19 stats (T1-T2)/T1 Min... Open at page → 48 Page 48 0.5 1 1.5 Wavelength[Mm] Figure6.3 ThetransmittanceofasingleKBrwindowasmeasuredbythe Vis/NIRSCF.Thelowercurveisthestandarddeviationofthetransmittance measurements. ForthewindowtransmissionmeasurementsmadebytheFTIRspectro... Open at page → 49 Page 49 0.92 > 0.88 I ' 1 ' ^ ^ ' 1 i i • 1 • 1 0 5 10 15 20 Wavelength [\im] Figure6.4 Relativespectralresponsivityofthebolometerwithuncertainties typicaloftheVis/NIRandIRspectralregionsshown. 6.1.2AbsoluteResponsivityTiePoints... Open at page → 50 Page 50 Wavelength [|jnn] Figure6.5 Theradiantpowerresponsivityofthepyroelectricdetectorusedfor scaletransferfromtheHACRtothebolometer. Thecomparisonofthebolometertothepyroelectrictransferdetectordeterminedthebolometer responsiv... Open at page → 51 Page 51 6 7 8 9 10 11 12 Wavelength[Mm] Figure6.6 Bolometerspectralradiantpowerresponsivityastransferredusing thepyroelectricdetector. Table6.1 Bolometerspectralradiantpowerresponsivityuncertaintybudget astransferredfromthepyroe... Open at page → 52 Page 52 a600g/mmgrating.)ThistransferdetectoristiedtotheHACRfrom0.8|imto1.8|imviaa calibrationchainthatincludessingleelementandtrapconfiguration Sidetectorsanda pyroelectricdetectorandtheVis/NIRSCF[LBP98].Theresultingbolometerre... Open at page → 53 Page 53 Gecomparison 0.9^imto1.8\im 1.5\imto1.8|Am 1.31 correctionfactor/ uncertaintysources C^%[%1 C /C ^ c /L ^ ^ 1.1014 0.05 1.1134 0.10 1.1184 0.05 VaiiCb 1.3959 0.47 1.3987 0.18 1.4807 0.07 varies ^bias 1.0189 0.03 1.0197 0... Open at page → 54 Page 54 Table6.3 Bolometerspectralradiantpowerresponsivityuncertaintybudget astransferredfromtheSidetector.Thelastcolumnindicateswhetherthe uncertainty isconstantoverthespectralrangeorvarieswithwavelength. Sicomparison 1 0.6|imt... Open at page → 55 Page 55 responsivityuniformity,andinvolvedamoredifficultcalibrationtransfer.Theoverallgoodfit ofthepredictedcurveshapetotheactualmeasurementsoverthe0.6|imto 11 range indicatesgoodself-consistency. Thisshouldbeemphasizedastheover... Open at page → 56 Page 56 fittoaline.AsshowninFigure6.9,thefitstayswithin±0.25%ofunityindicatingthatany systematictihingoftherelativecurveislessthanthisvalue. u * V v> c o a (A U QC 1.04 1.03 1.02 1.01 1 0.99 0.98 0.97 0.96 ' 1 1 r r C=0.39130 --... Open at page → 57 Page 57 u (0 u (/) o 0.398 0.396 0.394 0.392 0.390 -Assumes alluncerts.arestat. -Usingonlystat.uncerts. y=a+bX a=0.3919 b=0.00013 y=a+bX a=0.3915 b=0.00015 (a) 0.388 X. (|jm) mean ^"^ ' 10 0.398 -^Assumes alluncerts.arestat. —Us... Open at page → 58 Page 58 7. OperationalProceduresandComputerControl 7.1.1DataTakingProgram Allofthecomputercontrolanddatatakingisdonebyasinglemainprogram,whichhasbeen designedformaximumflexibility.Datamaybetakenasafunctionofanumberofparameters:... Open at page → 59 Page 59 7.1.4Bolometer -DUTComparisonProcedure(AbsoluteandRelative ResponsivityMeasurements) AfteralignmentofthebolometerandDUT,thepropersettingsofthedetectorpositionandgain parameterscanbeenteredintotheprogram.Thetypicalprocedu... Open at page → 60 Page 60 10. References BRM95 J.M.BridgesandA.L.Migdall,"Characterization ofArgonArcSourceinthe Infrared,"Metrologia,32,625-628(1995/96). BR077 J.M.BridgesandW.R.Ott,"VacuumUhravioletRadiometry. 3:TheArgon Mini-ArcasaNewSecondary... Open at page → 61 Page 61 KOS79 H.J.Kostkowski,TheRelativeSpectralResponsivityandSlit-Scattering FunctionofaSpectroradiometer, Chapter7inSelf-StudyManualonOpticalRadiation Measurements: PartI—Concepts,Chapters7,8,and9,F.E.Nicodemus,Editor,Natl. B... Open at page → 62 Page 62 THESP250SERIESONNISTMEASUREMENTSERVICES* SP250-1 SpectralRadianceCalibrations PB87179883 SP250-2 FarUltravioletDetectorStandards PB87227609 SP250-3 RadiometricStandards intheVacuumUltraviolet PB87227625 SP250-4 FrickeDos... Open at page → 63 Page 63 THESP250SERIESONNISTMEASUREMENTSERVICES*-Continued SP250-46NISTMultifunctionCalibrationSystem SN003-003-03515-7 $2.75 SP250-47NISTCalibrationServiceforCapacitance StandardsatLowFrequencies SN003-003-03549-1 $7.00 SP250-4... Open at page → 64 Page 64 o 2 ECO o ™ ow o o o I CD CD 00 O CM O o CO Open at page →