Editedby JuanP.TorresandLluisTorner TwistedPhotons Related Titles Clarke,D. Meschede,D. StellarPolarimetry Optics, LightandLasers ThePracticalApproachtoModernAspects 2010 ofPhotonicsandLaserPhysics ISBN:978-3-527-40895-5 2007 Ro¨mer,H. ISBN:978-3-527-40628-9 Theoretical Optics Busch,K.,Lo¨lkes,S.,Wehrspohn,R.B., AnIntroduction Fo¨ll,H.(eds.) 2009 PhotonicCrystals ISBN:978-3-527-40776-7 AdvancesinDesign,Fabrication,and Characterization Wang,L.V.,Wu,H.-i 2004 BiomedicalOptics ISBN:978-3-527-40432-2 PrinciplesandImaging 2007 ISBN:978-0-471-74304-0 Edited by Juan P. Torres and Lluis Torner Twisted Photons Applications of Light with Orbital Angular Momentum TheEditors AllbookspublishedbyWiley-VCHare carefullyproduced.Nevertheless,authors, Prof.JuanP.Torres editors,andpublisherdonotwarrantthe UniversitatPolitecnicadeCatalunya informationcontainedinthesebooks, ICFO-TheInstituteofPhotonicSciences includingthisbook,tobefreeoferrors. MediterraneanTechnologyPark Readersareadvisedtokeepinmindthat AvCanalOlimpics/n statements,data,illustrations,procedural 08860Castelldefels(Barcelona) detailsorotheritemsmayinadvertentlybe Spain inaccurate. [email protected] LibraryofCongressCardNo.:appliedfor Prof.LluisTorner UniversitatPolitecnicadeCatalunya BritishLibraryCataloguing-in-Publication ICFO-TheInstituteofPhotonicSciences Data MediterraneanTechnologyPark Acataloguerecordforthisbookisavailable AvCanalOlimpics/n fromtheBritishLibrary. 08860Castelldefels(Barcelona) Spain Bibliographicinformationpublishedbythe [email protected] DeutscheNationalbibliothek TheDeutscheNationalbibliothek liststhispublicationintheDeutsche Nationalbibliografie;detailedbibliographic dataareavailableontheInternetat <http://dnb.d-nb.de>. 2011WILEY-VCHVerlag&Co.KGaA, Boschstr.12,69469Weinheim,Germany Allrightsreserved(includingthoseof translationintootherlanguages).Nopart ofthisbookmaybereproducedinany form–byphotoprinting,microfilm,orany othermeans–nortransmittedortranslated intoamachinelanguagewithoutwritten permissionfromthepublishers.Registered names,trademarks,etc.usedinthisbook, evenwhennotspecificallymarkedassuch, arenottobeconsideredunprotectedbylaw. Typesetting LaserwordsPrivateLtd., Chennai,India PrintingandBinding FabulousPrintersPteLtd., Singapore CoverDesign Grafik-DesignSchulz, Fußgo¨nheim PrintedinSingapore Printedonacid-freepaper ISBN:978-3-527-40907-5 V Contents Preface XI ListofContributors XV ColorPlates XIX 1 TheOrbitalAngularMomentumofLight:AnIntroduction 1 LesAllenandMilesPadgett 1.1 Introduction 1 1.2 ThePhenomenologyofOrbitalAngularMomentum 4 References 9 2 VortexFlowofLight:‘‘Spin’’and‘‘Orbital’’FlowsinaCircularly PolarizedParaxialBeam 13 AleksandrBekshaevandMikhailVasnetsov 2.1 Introduction 13 2.2 SpinandOrbitalFlows:GeneralConcepts 14 2.3 TransverseEnergyFlowsinCircularlyPolarizedParaxialBeams 15 2.4 OrbitalRotationwithoutOrbitalAngularMomentum 21 2.5 Conclusion 22 References 23 3 HelicallyPhasedBeams,andAnalogieswithPolarization 25 MilesPadgett 3.1 Introduction 25 3.2 RepresentationofHelicallyPhasedBeams 26 3.3 ExploitingtheAnalogousRepresentationsofSpinandOrbitalAngular Momentum 27 3.3.1 RotationalDopplerShiftsandGeometricalPhase 27 3.3.2 ModeSortingusingGeometricPhase 29 3.3.3 EntanglementofSpatialModes 30 3.3.4 PhotonDragandtheMechanicalFaradayEffect 32 3.4 Conclusions 33 References 34 TwistedPhotons:ApplicationsofLightwithOrbitalAngularMomentum. EditedbyJuanP.TorresandLluisTorner Copyright2011WILEY-VCHVerlagGmbH&Co.KGaA,Weinheim ISBN:978-3-527-40907-5 VI Contents 4 TrappingandRotationofParticlesinLightFieldswithEmbedded OpticalVortices 37 MichaelMaziluandKishanDholakia 4.1 Introduction 37 4.2 Laguerre–GaussianLightBeams 38 4.3 OriginofOpticalTorquesandForces 41 4.3.1 IntuitivePictureofOpticalForces 41 4.3.2 AngularMomentumwithinGeometricOptics 43 4.3.3 ParaxialBeams 44 4.3.4 Maxwell’sStressTensor 45 4.3.5 LinearMomentumTransfer 49 4.3.6 AngularMomentumTransfer 50 4.3.7 PolarizationSpinMomentum 50 4.4 OpticalVortexFieldsfortheRotationofTrappedParticles 51 4.4.1 StudiesofRotationofTrappedObjectsusingOptical VortexFields 51 4.5 OpticalVortexFieldsforAdvancedOpticalManipulation 57 4.6 Conclusions 61 Acknowledgments 62 References 62 5 OpticalTorquesinLiquidCrystals 67 EnricoSantamatoandBrunoPiccirillo 5.1 TheOpticalReorientationandthePhoton AngularMomentumFlux 70 5.1.1 DynamicalEquationsofLiquidCrystals 71 5.1.2 AngularMomentumFluxes 73 5.2 DynamicalEffectsInducedinLiquidCrystalsbyPhotonSAM andOAMTransfer 78 5.2.1 ExperimentsonOAMTransferinLiquidCrystals 81 5.2.1.1 OrbitalPhotonAngularMomentumTransferwithUnpolarized Light 83 5.2.1.2 InvestigationoftheCombinedEffectoftheSpinandOrbitalPhoton AngularMomentumTransferwithLinearlyPolarizedLight 83 5.2.1.3 InvestigationoftheCombinedEffectoftheSpinandOrbitalPhoton AngularMomentumTransferwithCircularlyPolarizedLight 85 5.3 Conclusions 89 References 90 6 DrivingOpticalMicromachineswithOrbitalAngularMomentum 93 VincentL.Y.Loke,TheodorAsavei,SimonParkin,NormanR.Heckenberg, HalinaRubinsztein-Dunlop,andTimoA.Nieminen 6.1 Introduction 93 6.2 Symmetry,Scattering,andOpticallyDrivenMicromachines 93 6.3 ExperimentalDemonstration 96 Contents VII 6.3.1 APreliminaryDesign 96 6.3.2 Fabrication 97 6.3.3 OpticalTrappingandRotation 97 6.3.4 OpticalMeasurementofTorque 98 6.3.5 Discussion 100 6.4 ComputationalOptimizationofDesign 102 6.4.1 ComputationalModelingofMicrorotors 102 6.4.2 PerformanceofaFour-ArmedRotor 105 6.4.3 Discussion 111 6.5 Conclusion 113 References 113 7 RotationalOpticalMicromanipulationwithSpecificShapesBuiltby Photopolymerization 117 Pe´terGalaja,Lo´ra´ndKelemen,La´szlo´Oroszi,andPa´lOrmos 7.1 Introduction 117 7.2 MicrofabricationbyPhotopolymerization 118 7.2.1 FabricationbyScanningaSingleFocusedLaserBeam 118 7.2.2 ParallelPhotopolymerizationusingDiffractiveOptics 120 7.3 Light-DrivenRotors,Micromachines 121 7.3.1 Propeller 121 7.3.2 PropellerwithReversedDirectionofRotation 124 7.3.3 ComplexMicromachines 126 7.4 IntegratedOpticalMotor 128 7.5 AngularTrappingofFlatObjectsinOpticalTweezersFormedby LinearlyPolarizedLight 131 7.6 TorsionalManipulationofDNA 134 7.6.1 DirectMeasurementofTorque 135 7.7 Conclusion 138 Acknowledgment 139 References 139 8 SpiralPhaseContrastMicroscopy 143 ChristianMaurer,StefanBernet,andMonikaRitsch-Marte 8.1 PhaseContrastMethodsinLightMicroscopy 143 8.2 FourierFilteringinOpticalImaging 144 8.3 SpiralPhaseFourierFiltering 146 8.3.1 IsotropicEdgeEnhancement 148 8.3.2 PseudoreliefImages 149 8.3.3 SpiralFringeMetrologywithSPC 150 8.4 ImplementationandPerformance 151 8.5 Conclusions 152 References 152 VIII Contents 9 ApplicationsofElectromagneticOAMinAstrophysicsandSpace PhysicsStudies 155 BoThide´,NicholasM.EliasII,FabrizioTamburini,SiavoushM. Mohammadi,andJose´T.Mendon¸ca 9.1 Introduction 155 9.2 UbiquitousAstronomicalPOAM 156 9.3 ApplicationsofPOAMinAstronomy 158 9.3.1 Sub-RayleighResolution 159 9.3.2 OpticalVorticeswithStarlight 162 9.4 ApplicationsofPOAMinSpacePhysics 165 9.A. Appendix:TheoreticalFoundations 169 9.A.1 ClassicalFieldPicture 169 9.A.2 PhotonPicture 170 References 175 10 OpticalVortexCatStatesandtheirUtilityforCreatingMacroscopic SuperpositionsofPersistentFlows 179 EwanM.Wright 10.1 Introduction 179 10.2 OpticalVortexCatStates 181 10.2.1 LinearFiberPropagation 181 10.2.2 QuantumFiberPropagation 182 10.2.3 OpticalVortexCatStateviaSelf-PhaseModulation 184 10.2.4 Photonic-CrystalFibers 186 10.2.5 OtherSchemes 188 10.3 MacroscopicSuperpositionofPersistentFlows 189 10.3.1 OpticalLight-ShiftPotential 189 10.3.2 RingTrapandQuantumStirring 190 10.3.3 MatterWavesonaRing 191 10.3.4 MacroscopicSuperpositionofPersistentFlows 192 10.3.5 Discussion 194 10.4 SummaryandConclusions 195 References 195 11 ExperimentalControloftheOrbitalAngularMomentumofSingle andEntangledPhotons 199 GabrielMolina-TerrizaandAntonZeilinger 11.1 IntroductiontothePhotonOAM 199 11.2 ControloftheOAMStateofaSinglePhoton 201 11.3 ControloftheOAMStateofMultiplePhotons 203 11.4 ApplicationsinQuantumInformation 207 11.5 Discussion 209 11.6 Conclusion 211 References 211 Contents IX 12 RotatingAtomswithLight 213 KristianHelmersonandWilliamD.Phillips 12.1 Introduction 213 12.2 OrbitalAngularMomentumofLight 213 12.3 TheMechanicalEffectsofLight 214 12.4 RotatingBose–EinsteinCondensates 215 12.4.1 ExperimenttoTransferOrbitalAngularMomentumtoaBEC ((cid:1)=0) 216 12.4.2 EfficiencyoftheOAMTransferProcess 218 12.5 MeasuringtheRotationalMotionoftheAtoms 220 12.5.1 InterferenceoftheRotatingStatewithaNonrotatingState 220 12.5.2 InterferenceoftheRotatingStatewithaCounterrotatingState 222 12.5.3 ObservationofFork-LikeInterferenceStructure 223 12.5.4 MeasurementoftheDopplerShiftoftheRotatingAtoms 223 12.6 GeneratingOtherRotationalStatesofAtoms 224 12.6.1 VorticesofHigherCharge 224 12.6.2 RotationalStatesofMultilevelAtomicCondensates 227 12.6.3 MatterwaveAmplificationofaVortexState 228 12.7 Supercurrents 230 12.7.1 GenerationofaSupercurrentinaBEC 230 12.8 Conclusion 231 Acknowledgments 232 References 232 Index 237