Zemax-How to Create a Simple Non-sequential system

ZEMAXUsers'KnowledgeBase-http://www.zemax.com/kbHowtoCreateaSimpleNon-SequentialSystemhttp://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-SystemByNam-HyongKimPublishedon08/23/2005Thisarticleexplains:zHowtoenterandeditnon-sequentialobjectsinthenon-sequentialeditorzHowtodrawraysonthelayoutplotstogetaqualitativefeelfortheopticalsystemperformancezHowtotracelargenumbersofraystogetquantitativedataonsystemperformanceThelensfilerepresentingthefinalsystemisincludedaszippedfile,whichcanbedownloadedfromthelastpageofthisarticle.IntroductiontoNon-SequentialRayTracing.Thereare2distinctray-tracingmodesinZEMAX;sequentialandnon-sequential.Thekeydifferencesbetweensequentialandnon-sequentialmodesare:SequentialmodezItismainlyusedfordesigningimagingandafocalsystemszSurfacesaredefinedintheLensDataEditorzRaycanonlyintersecteachsurfaceonceandhastodoitinaspecified-sequential-order(i.e.surface#0then#1,#2…)andhencethenamesequentialraytracingzRaycanonlyreflectifthesurfacematerialtypeisMIRROR.Partialreflectionsfromrefractivesurfaces(Fresnelreflections)areaccountedfortotheextentofcalculatingthecorrectrefractedenergy,includingtheeffectsondielectricormetallicmirrorszEachsurfacehasitsownlocalcoordinatesystem.Thepositionofeachsurfacealongtheopticalaxisisreferencedtotheprevioussurface.Inotherwords,the“Thickness”columnintheLensDataEditorreferstothedistancefromcurrentsurfaceandnotfromaglobalreferencepointNon-sequentialmodezItisprimarilyusedfornon-imagingapplicationssuchasilluminationsystemsand/orstray-lightanalysiszSurfacesorvolumeobjectsaredefinedintheNon-SequentialComponentEditorzMechanicalcomponentsmaybeeasilyimportedfromCADprograms,sothatfullOpto-MechanicalanalysismaybeundertakenzAraycanintersectthesameobjectmorethanonceandcanintersectmultipleobjectsinanyorder;hencethenamenon-sequentialzEachobjectisreferencedtoaglobalcoordinate,unlessspecifiedotherwisezPartiallyreflectedrayscanbegeneratedandtracedfromarefractiveinterface,inadditiontotracingtherefractedray.Thisisreferredtoasraysplitting.Henceboththereflectedandrefractedrayscanbetraced.zImaging-systempropertiessuchasstoplocation,entranceandexitpupil,field,systemapertureetc.thatexistinsequentialsystemsmaynotbemeaningfulinnon-sequentialsystemszThemainanalysisfeatureinnon-sequentialmodeisthedetectorray-trace,whichgivesspatialandangulardataonincoherentorcoherentrays.Inaddition,ahybridmode("non-sequentialwithports"or"mixed-mode")existsinwhichsequentialandnon-sequentialray-traceareusedinthesamesystem.Fulldetailsofnon-sequentialZEMAXcapabilitiesaregiveninchapter12oftheusermanual.SettingupBasicSystemPropertiesPágina1de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Wewillcreateanon-sequentialsystemwithafilamentsource,aparabolicreflectorandaplano-convexlensthatcoupleslightintoarectangularlightpipe,asshowninthelayoutbelow.Wewillalsotraceanalysisraystothedetectorstoobtaintheirradiancedistributionatvariouspointsintheopticalsystem.Hereiswhatwewillfinallyproduce:Página2de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...IfZEMAXisnotrunning,pleasestartitnow.Bydefault,ZEMAXstartsinsequential/mixedmode.Toswitchtopurenon-sequentialmode,openZEMAXandclickFile>NonSequentialMode.Onceinpurenon-sequentialmode,thewindowtitlebaroftheeditorwilldisplaytheNon-SequentialComponentEditorinsteadoftheLensDataEditorwheninsequentialmode.TheLensDataEditorisusedonlyinsequentialormixed-modesystems.Página3de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Forthisexercise,wewillsetthesystemwavelength,specifiedunderSystem>Wavelengths,to0.587µm.WewillalsosettheunitsunderSystem>GeneralUnittabasfollows(default).Página4de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...InadditiontoradiometricirradianceunitsuchasWatt.cm-2,youcanspecifyphotometricandenergyunitssuchaslumen.cm-2orjoule.cm-2.Wewillchoosethedefaultradiometricunitsforthisexercise.CreatingtheReflectorInsertafewlinesinthenon-sequentialcomponenteditorbypressingthe“Insert”keyonyourkeyboard.Inthefirstpartofthedesign,wewillcreateafilamentsourcecollimatedbyaparabolicreflector.Wewillthenplaceadetectorobjectatsomedistance+Zandlookattheirradiancedistributiononadetector.Makethefirstobjectaparabolicreflectorbydoubleclicking(leftclicking)onthe“Objecttype”columnofObject1intheeditorandopeningtheObjectPropertywindow.UndertheTypetabsettheTypetoStandardSurfaceandclickOK.Intheeditor,typethefollowingparametersinthecorrespondingcolumnofStandardSurfaceObject.Forsomeoftheparameters,youmighthavetoscrolltotherightoftheeditortoseethetitlecolumndisplaythedesiredparametername.Página5de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Material:MirrorRadius:100Conic:-1(parabola)MaxAper:150MinAper:20(centerholeinthereflector)AllotherparametersshouldbeleftasdefaultYoucanopentheNSC3DlayoutunderAnalysis>Layout>NSC3DLayoutmenuand/ortheNSCShadedmodel(Analysis>Layout>NSCShadedmodel)toseewhatthisreflectorlookslike.CreatingtheSourceChangetheobject#2type(currentlyaNullObject)intheeditortoSourceFilamentobjectbyrepeatingthepreviousstepandchoosingSourceFilamentinthepropertywindow.Página6de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...WewanttheSourceFilamenttobeatthefocusoftheparabolicreflectortocollimatethebeam.Thefilamentcoilhas10turnswithoveralllengthof20mmandradiusofturnof5mm.TheparameterenteredfortheSourceFilamentintheeditorshouldbe:Página7de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Zposition:50(focusoftheparabolicreflector)#LayoutRays20#AnalysisRays5000000Length:20Radius5Turns10Updatethe3DlayoutbyclickingUpdateintheNSC3DLayoutmenu.Thelayoutshows20raysemanatingfromthesourcefilament,asspecifiedinthe#LayoutRaysparameter.RotatingtheSourceThesourceisorientedalongtheZaxis,butsupposewewanttoorientitalongtheXaxis;wewouldneedtorotatethesourceobjectby90degreesabouttheYaxis.Enter90fortheTiltAboutYparameterofthesource.Página8de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...ThedefaultYZplaneviewofthelayoutshowthefilamentbeingorientedalongtheXaxis,however,theXZplaneviewrevealsthatthefilamentisshiftedtowards+Xaxis.Torotatethelayout,changethelayoutviewangleintheLayoutsettingswindow(clickSettingsintheLayoutmenu).Youcanalsorotatethedrawingbypressingtheleft,rightupdownarrowkeyandPageUpandPageDownkeyonyourkeyboard.Página9de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...ThereasonforthedecenterisbecausetherotationaxisoftheSourceFilamentisnotatthecenteroftheobjectbutattheend.TocenterthesourceintheXaxis,enter-10intheXpositioncolumn.Página10de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Updatethelayoutanditwillnowshowthedesiredfilamentlocationandorientation.PlacingaDetectorNextstepistoplaceadetectorobjectatsomedistancefromthesourcetostudytheirradiancedistributionatthatlocation.Makethe3rdobjectintheeditora“DetectorRect”andenterthefollowingparameters.Zposition:800Material:Blank(donottypetheword"Blank"butleavethecellempty)XHalfWidth:150YHalfWidth:150#XPixels:150#YPixels:150Color:1(detectordisplaysinversegreyscale)AllotherparametersasdefaultTheYZplaneview(default)ofthelayoutshows:Observethatthelayoutshowstheraysgoingthoughthedetector.Thedetectoristotallytransparentsincethematerialtypeisair(blankintheeditor).Página11de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...TracingAnalysisRaystotheDetectorToseetheopticalintensityatthedetector,weneedtoopentheDetectorViewerbyclickingAnalysis>Detectors>DetectorViewer.Youwillnoticethatthedetectorviewerisblankwithzerototalpower,eventhoughweseeraysreachingthedetectorinthelayout.Thereasonisbecausetheraysaretracedseparatelyforthelayoutandforthedetectorviewer.Weneedtotracetheanalysisraystothedetectorfirsttoseetheresult.Thenumberofraystracedtothedetectorisspecifiedinthe“#AnalysisRays”parametercolumnoftheSourceFilamentobjectintheeditor,whichisusuallyalargenumber:5millioninthiscase.Remember,layoutraysdonotaffecttheDetectorViewerresults;onlyanalysisraysdo.Totraceanalysisraystothedetector,opentheDetectorControlwindowunderAnalysis>Detectors>RayTrace/DetectorControl.Página12de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...AlwaysremembertotheclearthedetectorbypressingtheClearDetectorbutton,ifyoudonotwishtoaddtheresultfromtheprevioustracetothecurrentone.PressClearDetectorsthenTracebuttonfollowedbyExit.Thedetectorviewerwilldisplaytheirradiancedistribution,revealingthehotspotscausedbythefilamentsource.IfyourDetectorViewerlooksdifferent,openthedetectorviewersettingswindowandmakesurethesettingsareasfollows.Página13de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...YoucanalsoseethedetectortraceresultintheNSCShadedModelLayoutbyselecting“Colorpixelsbylastanalysis”optioninthesettings.Página14de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...AddingaPlano-ConvexLensNowthatwehaveasourceandareflector,wewilladdarefractiveplano-convexlens10mmtotheright(+Z)ofthedetector.InsertalineafterDetectorRectintheeditorandmakethetypeStandardLenswiththefollowingparametervalues.RefObject:3ZPosition:10Material:N-BK7Radius1:300Clear1:150Edge1:150Thickness:70Clear2:150Edge2:150Updatethe3DLayoutPágina15de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Noticehowwereferencedthepositionofthelenstoobject3(DetectorRect)byenteringthevalue3intheRefObjectcolumnandspecifiedtheZpositionvalueof10,insteadofreferencingtoglobalvertex(RefObject=0)andspecifying860mmfortheZpositionparameter.Withthelenspositionedreferencedtothedetector,thelenswillalwaysbe10mmtoright(+Z)ofthedetectorregardlessofthedetectorposition.Thisishowrelativeobjectpositionsarespecifiedinnon-sequentialmode.Toseehowthefocusedbeamlookslike,placeanotherdetector650mmtotheright(+Z)ofthelenswiththefollowingparameters.RefObject:4Zposition:650Material:BlankXHalfWidth:100YHalfWidth:100#XPixels:150#YPixels:150Color:1Allotherparameters:DefaultUpdatethe3DLayoutPágina16de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...TracingAnalysisRaysandAccountingforPolarizationLossesOpenanotherDetectorViewerbyclickingAnalysis>Detectors>DetectorViewerandmakethesettingsasfollows.Now,wearereadytotraceanalysisraystothedetectoragain.SincetheN-BK7lensisuncoated,weneedtoaccountforthereflectionlosses(Fresnelreflection),thusneedtoenable“UsePolarization”optionintheDetectorControlwindow.(Notethatwearenotsplittingraysatthistime,andsothereflectionlossesareaccountedfor,butthereflectedenergyisnotbeingpropagated.Clicking"SplitRays"willcreatechildraysthattakethereflectedenergyaway.)Página17de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Thetotalpower,reportedintheDetectorViewerisnowaccountingforreflectionlossesandbulkabsorptioninthelens.AddingaRectangularLightpipeAsafinalstep,wewilladdarectangularacryliclightpipe20mmtotheright(+Z)oftheDetector#5.AddRectangularVolumeobjectintheeditor,afterDetector#5,withthefollowingparameters:RefObject:-1Zposition:20Página18de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Material:AcrylicX1HalfWidth70Y1HalfWidth:70Zlength:2000X2HalfWidth:70Y2HalfWidth:70Allotherparameters:DefaultWhenenteringthematerialtypeAcrylic,youmightgetthefollowingmessage.ClickYesandZEMAXwilladdtoyourfiletheMISCglasscatalog,inwhichthematerialAcrylicisdefined.Thistime,wehavesettheRefObjectparameter-1,whichrepresentthepreviousobjectintheeditor(Object#5DetectorRect).Thisissameastyping“5”forthisparameter.SpecifyingrelativeobjectusingnegativenumberfortheRefObjectisusefulwhengroupofobjectsintheeditoraretobecopiedandpastedintothesameordifferentnon-sequentialcomponenteditor.PlaceanotherDetectorRectasobject#7intheeditorwithfollowingparameters.RefObject:-1(referencedtoRectangularVolume,usingtherelativeobjectreference)Zposition:0(wewillchangethisvaluelater)Material:AbsorbXHalfWidth:100YHalfWidth:100#XPixels:150#YPixels:150Color:1Allotherparameters:DefaultPágina19de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...UsingaPickupSolvetoPositiontheDetectorTheupdates3DlayoutwillshowthefollowingThematerialtypewassettoAbsorbtomakethedetectoropaqueratherthantransparent,evidentfromthelayout.SincewereferencedtheDetector#7totheRectangularVolumeandsettheZpositionaszero,theDetectorislocatedatthefrontsurfaceofthelightpipe.Wewanttoplacethisdetector10mmtotheright(+Z)ofthelightpipe,hencetheZpositionvalueshouldbe2010mm(thicknessofRectangularVolume+10).IfwechangethethicknessoftheRectangularVolumetoadifferentvalue,theZpositionofthedetector#7shouldalsobechanged.Forconvenience,insteadoftypingthevalue2010mmintheeditor,wewillplacea“Pickupsolve”fortheZpositionofthedetector.ThentheZpositionvalueintheeditorwillautomaticallybecalculatedtobe10pluswhateverthethicknessofobject6is.DoubleorrightclickontheZpositionparameterofobject#7intheeditortoopenthesolvewindow.Página20de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...Typethefollowingparameters.TheParameter#0intheNon-SequentialComponentEditorcorrespondstothe“Material”column,sofortheRectangularVolumeobject,parameter#3correspondsto“ZLength”.AfterpressingOK,aletter“P”willappearsnexttotheparameterintheeditorindicatingthepresenceofPickupsolve.Ray-TracingtheCompleteSystemOpenathirddetectorviewertoviewdetector#7andre-tracethedetector.Remembertousethepolarizationoptionandtoclearthedetectorsbeforetracingthedetector,intheDetectorControlwindow.ThetracetimeonaDellPrecision370machinerunningWindowsXPPro,3.4GHzPentium4and1GBofPágina21de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...memoryisabout2minutes.Thedetectorviewershowsthatthelightpipehaseffectivelyremovedthehotspotsmakingtheirradiancedistributionalmostuniform.Thezippedfileofthecompletesystemisincludedwiththisarticleasreference.TheNSCShadedModelcanincludethedetectortraceresults.Forthelayoutbelow,multiple-configurationcapabilityofZEMAXwasusedtodisplaythesystemwithandwithoutthedetectorresultsinthesamelayout(wewillnotgointodetailsonhowtodothis).Usersareencouragedtolearnaboutthefullnon-sequentialcapacitiesofZEMAXbyreferencingtheusermanual,readingotherknowledgebasearticlesandstudyingsamplefilesthatcomeswithZEMAX.Página22de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...SummaryandReferencesThisarticlehasshownhowtocreateandanalyzeasimplenon-sequentialsysteminZEMAX.Insummary:zTherearemajordifferencesbetweenthesequentialandnon-sequentialZEMAXthatusersneedtoawareofbeforeattemptingtodesignanon-sequentialsystemzLayoutraysdonotaffectdetectortraceresultszToaccountforFresnellossesandbulkabsorption,thepolarizationoptionshouldbeusedwhentracinganalysisraystothedetectorReferences:ZEMAXuserManualPágina23de2315/10/2005http://www.zemax.com/kb/articles/33/1/How-to-Create-a-Simple-Non-Sequential-Sys...