简介:Wepresentamethodthataccuratelymeasureslargeopticalsurfacesbeforepolishingusingalasertracker.Usingthescanningmodeofthelasertrackerconsiderablyimprovesmeasurementefficiencyandminimizesthedominanterrorscausedbyenvironmentalchange.WeusethismethodtomeasureaΦ1.3-masphericmirrorandobtainameasurementuncertaintyof0.72μm(rootmeansquare,RMS).
简介:Diffractiveopticsisanimportanttechniqueforbeamshapingwithhighlightefficiencyandstrongdiffractionpatternflexibility.Sincethediffractionangleislimitedbytheunitsizeofthediffractiveopticalelement(DOE),thesizeoftherequireddiffractionpatternisalwaysrathersmall.InthisLetter,refractive/diffractivehybridopticalelements(RDHOEs)consistingofaDOEandalensareusedtorealizebeamshapingforalargediffractionpattern.Thelens,asthecomponentoftheRDHOEs,cannotonlybeconcavebutalsoconvex,andthedoublesamplingFresneldiffractionalgorithmisdevelopedforthedesignofthesetwotypesofRDHOEs.Thesimulationandexperimentalresultsprovidesolidevidencetodemonstratetheproposedmethodwiththepurephasespatiallightmodulator.
简介:Thenumericalstudyontheperformanceoflarge-mode-area(LMA)fiberscoiledontoaspoolinhighpoweramplifieriscarriedoutasthebend-induceddistortionoffibermodesseverelyaffectstheoutputcharacteristicsofamplifiersystems.Thevariationsforhigh-ordermodebenddistortionwithdifferentorientationsrelativetotheplaneofthefiberbendareobservedandshown.Concerningthepracticalapplications,abend-resistantLMAfiberwiththemodearealargerthan1000μm2andexcellenthighordermodesuppressionisdesignedcompletelybyoptimizingtherefractiveindex(RI)anddopantprofile.TheresultsindicatethatahybridprofileofRIanddopantisthebestchoiceforLMAfiberwithcoiling.
简介:Acarriermethodforseparatingout-of-planedisplacementfromin-planecomponentsbasedonlargeimage-shearingshearographyispresented.Areferencesurfaceisfixedonthesideofatestobject.Theyareilluminatedbytwoexpandedsymmetricilluminationsrespectively.Thecarrierisintroducedbyrotatingthereferencesurfacetomodulatethedisplacementofanobject.ByusingFouriertransformtodemodulatethemodulatedfringepattern,twophasemaps,whichincludeout-of-planeandin-planedisplacements,canbeobtained.Thentheout-of-planedisplacementcanbeeasilyseparatedfromin-planedisplacementbysubtractionandadditionofthetwounwrappedphasedistributions.Theprincipleofthemethodispresentedandprovedbyatypicalthree-point-bendingexperiment.Experimentalresultsshowthatthemethodenjoyshighvisibilityofcarrierfringes.Thesystemdoesnotneedaspecialbeamasareferencelightandhassimpleopticalsetup.更多还原
简介:Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.