Cloak of invisibility - Wikipedia

A cloak of invisibility is a fictional theme. In folklore, mythology and fairy tales, a cloak of invisibility appears either as a magical item used by ... Cloakofinvisibility FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Mythicalobjectthatgrantsinvisibility CloakofinvisibilityAlberichputsontheTarnkappeandvanishes;illustrationbyArthurRackhamtoRichardWagner'sDasRheingoldPlotelementfromFolkloreandfairytalesFirstappearanceAncientGenreFolkloreandfairytalesIn-storyinformationTypeMagicalcapeFunctionRendersthewearerinvisible Acloakofinvisibilityisafictionaltheme.Infolklore,mythologyandfairytales,acloakofinvisibilityappearseitherasamagicalitemusedbyduplicitouscharactersoranitemwornbyaherotofulfillaquest.ItisacommonthemeinWelshandGermanicfolklore,andmayoriginatewiththecapofinvisibilityseeninancientGreekmyths.Themotiffallsunder"D1361.12magiccloakofinvisibility"intheStithThompsonmotifindexscheme. Contents 1Infiction 1.1Tarnkappe 1.2Modernadaptations 2Inscience 2.1Problemsofrefractionandopacity 2.2Acousticcloaking 3Seealso 4References 5Bibliography 6Furtherreading 7Externallinks Infiction[edit] Cloaksofinvisibilityaremagicalitemsfoundinfolkloreandfairytales.SuchcloaksarecommoninWelshmythology;a"MantleofInvisibility"isdescribedinthetaleCulhwchandOlwen(c. 1100)asoneofKingArthur'smostprizedpossessions.[1]Themantleisdescribedagain,andinmoredetail,[1]intheBreuddwydRhonabwy,andislaterlistedasoneoftheThirteenTreasuresoftheIslandofBritain.AsimilarmantleappearsintheSecondBranchoftheMabinogi,inwhichitisusedbyCaswallawntoassassinatethesevenstewardsleftbehindbyBrantheBlessedandusurpthethrone.[1][2] IntheEnglishfairytaleJacktheGiantKiller,theheroisrewardedwithseveralmagicalgiftsbyagianthehasspared,amongthemacoatofinvisibility.IonaandPeterOpieobserveinTheClassicFairyTales(1974),thatJack'scoatmayhavebeenborrowedfromtheTaleofTomThumborfromNorsemythology,buttheyalsodrawcomparisonswiththeCelticstoriesoftheMabinogion.[3] ThecounterpartinJapanisthekakuremino(隠れ蓑),amagical"strawcape"or"raincoat"ofinvisibility.Inthefolktaleofthe"PeachBoy"Momotarō,oneofthetreasurestheherocollectsfromtheogresisacapeofinvisibility,parallelingthestoryofJackthegiant-slayer.[4] Tarnkappe[edit] Althoughoccurrencesinfairytalesarerare,[5]thecloakofinvisibilityappearsintheGermantaleTheTwelveDancingPrincesses(KHM133)andinTheKingoftheGoldenMountain(KHM92)inGrimm'sFairyTales.[6]ThecloakinGermanfairytalesmaybetraceabletothetarnkappe("cloakofconcealment"),[5]suchastheonethattheheroSîfrit(Siegfried)acquiresfromthedwarfAlberichintheMiddleHighGermanepicNibelungenlied.[7]TheGrimmsclarifythatSîfrit'skappeisacapethatcoversnotjusttheheadbutenshroudsthebody,thoughinlatertimestarnkappecametoberegardedasacapofinvisibility.Thetarnkappe(ortarnkeppelin[8])isalsoownedbythedwarfkingwhoisthetitlecharacterinLaurin.Indifferentpassagesorvariantmanuscriptsoftheseworks,thetarnkappeisalsoreferredtoasthetarnhût(mod.Ger.Haut"skin")[7][9]orhehlkappe(mod.Ger.hehlen"tohide").[10][11] Modernadaptations[edit] IntheoriginalepicNibelungenlied,thehero'scloaknotonlygrantshiminvisibility,butalsoincreaseshisstrength,towinovertheIcelandicqueenBrünhild.InRichardWagner'soperacycleDerRingdesNibelungen,thecloakbecomesamagichelmetcalledtheTarnhelm,whichalsoimpartstheabilitytotransformuponitswearer.WhenFritzLangadaptedNibelungenliedforthemoviescreeninhis1924filmDieNibelungen,SiegfriedusesaveilornetofinvisibilitygainedfromthedwarfAlberich.AnotherfilmfromthesameyeartouseacloakofinvisibilitywasRaoulWalsh'sTheThiefofBagdad,inwhichthecloakplaysapivotalrole. EdgarRiceBurroughsusestheideaofaninvisibilitycloakinhis1931novelAFightingManofMars.ThemovieEriktheVikinghumorouslydepictsthetitlecharacterusingacloakofinvisibility,whichhedoesnotrealizeapparentlyworksonlyonelderlymen.InTheLordoftheRings,Frodo,andtheothermembersoftheFellowshipoftheRing,weregivencloaksbytheElves,andSamwiseasked,"Arethesemagiccloaks?"ThecloakgiventoFrodocamouflagedhimsothattheenemycouldsee"nothingmorethanaboulderwheretheHobbitswere." CamouflagingcloaksformacentralplotelementinSamuelR.Delany's1975novelDhalgren. CloaksofinvisibilityalsoexistintheHarryPotterseriesofnovelsbyJ.K.Rowling.[12]HarryPotterusesaCloakofInvisibility,thatwaspasseddowntohimbyhisfather,tosneakintoforbiddenareasofhisschoolandremainunseen.ItislaterrevealedthatthisspecificcloakwasonceownedbyDeathhimself,makingitoneoftheDeathlyHallows. InTheSecretHistorybyDonnaTartt(1992),thecharacterRichardsays,"Ibecameexpertatmakingmyselfinvisible"..."Sundayafternoons,mycloakofinvisibilityaroundmyshoulders,Iwouldsitintheinfirmaryforsometimessixhoursatatime..." Inscience[edit] Mainarticle:Cloakingdevice OnOctober19,2006,acloakwasproducedthatroutedmicrowavesofaparticularfrequencyaroundacoppercylinderinawaythatmadethememergealmostasiftherewerenothingthere.Thecloakwasmadefrommetamaterials.Itcastasmallshadow,whichthedesignershopetofix. Thedeviceobscuresadefinedtwodimensionalregionandonlyataparticularmicrowavefrequency.Workonachievingsimilarresultswithvisiblelightisinprogress.[13][14]Othertypesofinvisibilitycloakarealsopossible,includingonesthatcloakeventsratherthanobjects. However,cloakingahuman-sizedobjectatvisiblewavelengthsappearstohavelowprobability.[15]Indeed,thereappearstobeafundamentalproblemwiththesedevicesas"invisibilitycloaks":[16] It'snotyetclearthatyou'regoingtogettheinvisibilitythateveryonethinksaboutwithStarTrekcloakingdeviceortheHarryPotter'scloak.Tomakeanobjectliterallyvanishbeforeaperson'seyes,acloakwouldhavetosimultaneouslyinteractwithallofthewavelengths,orcolors,thatmakeuplight. Ontheotherhand,agroupofresearchersconnectedwithBerkeleyLabandtheUniversityofCalifornia,Berkeleybelievethatcloakingatopticalfrequenciesisindeedpossible.Furthermore,itappearswithinreach.Theirsolutiontothehurdlespresentedbycloakingissuesaredielectrics.Thesenonconductingmaterials(dielectrics)areusedforacarpetcloak,whichservesasanopticalcloakingdevice.[17][18]Accordingtotheleadinvestigator: Wehavecomeupwithanewsolutiontotheproblemofinvisibilitybasedontheuseofdielectric(nonconducting)materials.Ouropticalcloaknotonlysuggeststhattrueinvisibilitymaterialsarewithinreach,italsorepresentsamajorsteptowardstransformationoptics,openingthedoortomanipulatinglightatwillforthecreationofpowerfulnewmicroscopesandfastercomputers. Furthermore,anewcloakingsystemwasannouncedinthebeginningof2011thatiseffectiveinvisiblelightandhidesmacroscopicobjects,i.e.objectsthatcanbeseenwiththehumaneye.Thecloakisconstructedfromordinary,andeasilyobtainablecalcite.Thecrystalconsistsoftwopiecesconfiguredaccordingtospecificparameters.Thecalciteisabletorefractthelightaroundasolidobjectpositionedbetweenthecrystals.Thesystememploysthenaturalbirefringenceofthecalcite.Fromoutsidethesystemtheobjectisnotvisible"foratleast3ordersofmagnitudelargerthanthewavelengthoflightinallthreedimensions."Thecalcitesolvesforthelimitationsofattemptingtocloakwithmetallicinclusions-thismethoddoesnotrequireananofabricationprocessashasbecomenecessarywiththeothermethodsofcloaking.Thenanofabricationprocessistime-consumingandlimitsthesizeofthecloakedregiontoamicroscopicarea.Thesystemworksbestundergreenlight.Inadditiontheresearchersappeartobeoptimisticaboutapracticalcloakingdeviceinthefuture:[19][20] Insummary,wehavedemonstratedthefirstmacroscopiccloakoperatingatvisiblefrequencies,whichtransformsadeformedmirrorintoaflatonefromallviewingangles.Thecloakiscapableofhidingthree-dimensionalobjectsthreetofourordersofmagnitudeslargerthanopticalwavelengths,andtherefore,itsatisfiesalayman'sdefinitionofaninvisibilitycloak:namely,thecloakingeffectcanbedirectlyobservedwithoutthehelpofmicroscopes.Becauseourworksolvesseveralmajorissuestypicallyassociatedwithcloaking:size,bandwidth,loss,andimagedistortion,itpavesthewayforfuturepracticalcloakingdevices Anotherdesigncallsfortinymetalneedlestobefittedintoahairbrush-shapedconeatanglesandlengthsthatwouldforcelighttopassaroundthecloak.Thiswouldmakeeverythinginsidetheconeappeartovanishbecausethelightwouldnolongerreflectoffit."Itlooksprettymuchlikefiction,Idorealize,butit'scompletelyinagreementwiththelawsofphysics,"saidleadresearcherVladimirShalaev,aprofessorofelectricalandcomputerengineeringatPurdue."Ideally,ifwemakeitrealitwouldworkexactlylikeHarryPotter'sinvisibilitycloak,"hesaid."It'snotgoingtobeheavybecausethere'sgoingtobeverylittlemetalinit." Furthermore,onApril30,2009,twoteamsofscientistsdevelopedacloakthatrenderedobjectsinvisibletonear-infraredlight.Unlikeitspredecessors,thistechnologydidnotutilizemetals,whichimprovescloakingsincemetalscausesomelighttobelost.Researchersmentionedthatsincetheapproachcanbescaleddownfurtherinsize,itwasamajorsteptowardsacloakthatwouldworkforvisiblelight.[21] Problemsofrefractionandopacity[edit] Theheadlinedclaimsthatlaboratoryresultswithmetamaterialsaredemonstrationsofprototypeinvisibilitycloaksconflictswithtwofactsresultingfromfundamentalcharacteristicsoftheunderlyingmetamaterialtechnology: Thesematerialsare,bynature,highlydispersive,hencelightpassingarounda"cloaked"objectwouldbestronglyrefracted(prismsarenotinvisible). Currentlylightpassingthroughthesematerialsispartiallyabsorbed,makingtheshieldpartiallyopaque. Perfectcloakingbymaterialsmaybeproblematic,whentakingcausalityintoaccount.[22] Acousticcloaking[edit] Thissectiondoesnotciteanysources.Pleasehelpimprovethissectionbyaddingcitationstoreliablesources.Unsourcedmaterialmaybechallengedandremoved.(August2014)(Learnhowandwhentoremovethistemplatemessage) Thoughperfectcloakingbasedoninvisiblepaintisimpossibleifdetectors(suchasmicrophones)andsources(suchasloudspeakers)areplacedroundavolumeandifaparticularformulaisusedtocalculatethesignalstobefedtothesources,perfectcloakingispossible.Suchperfectcloakingdoesrequirethattheinformationcanflowthroughthevolumefastenoughandthecalculationscanbeperformedfastenoughsothatthenecessaryinformationcangettothesourcesonthefarsideofthevolumefastenough.Asaresult,perfectcloakingforlightisstillprobablyatleastverydifficultifnotimpossible.Forsoundwaves,though,suchperfectcloakingispossibleinprinciple;anobjectcouldthereforebemadeinvisibletosonar,forexample. AccordingtoFermat'sPrinciple,lightfollowsthetrajectoryoftheshortestopticalpath,thatis,thepathoverwhichtheintegraloftherefractiveindexfunctionisminimal.Therefore,therefractiveindexofanopticalmediumdetermineshowlightpropagateswithinit.Consequently,byasuitablechoiceofrefractiveindexprofileforanopticalmedium,lightrayscanbebentaroundandmadetopropagateinclosedloops. Seealso[edit] Acousticcloak Cloakingdevice Invisibility Magicring References[edit] ^abcStephens(1998)p.479 ^Gantz,Jeffrey(1987).TheMabinogion.NewYork:Penguin.p. 80.ISBN 978-0-14-044322-6. ^Opie,Iona;Opie,Peter(1992)[1974].TheClassicFairyTales.OxfordUniversityPress.pp. 47–50.ISBN 978-0-19-211559-1. ^Eberts,RayE.;Eberts,CindelynG.(1995).ThemythsofJapanesequality.Prentice-Hall.p. 135.ISBN 9780131808034. ^abGregorsonCampbell,John(2004)[1900],Tatar,Maria(ed.),TheAnnotatedBrothersGrimm,JW.W.Norton&Company,p. 332,ISBN 978-0-393-05848-2 ^Jacob&WilheimGrimm."TheKingoftheGoldMountain".HouseholdTales. ^abGrimm,Jacob(1883)."XVII.WightsandElves".Teutonicmythology.Vol. 2.JamesStevenStallybrass(tr.).W.SwanSonnenschein&Allen.p. 462. ^Müllenhoff(1874)ed.,Laurin,v.485 ^Ettmüller(1829)ed.,KunechLaurin,v.39andnote,p.63 ^vonderHagen(1807)ed.,DerNibelungenLiedms.B1735,2614 ^Ettmüller(1829)ed., ^JohnSchwartz(October20,2006)."ScientistsTakeStepTowardInvisibility".TheNewYorkTimes. ^PeterN.Spotts(2006-10-20)."Disappearintothinair?Scientiststakesteptowardinvisibility".TheChristianScienceMonitor.Retrieved2007-05-05. ^SeanMarkey(2006-10-19)."FirstInvisibilityCloakTestedSuccessfully,ScientistsSay".NationalGeographicNews.Retrieved2007-05-05. ^RobertF.Service&AdrianCho(17December2010)."StrangeNewTricksWithLight".Science.330(6011):1622.Bibcode:2010Sci...330.1622S.doi:10.1126/science.330.6011.1622.PMID 21163994. ^ "InvisibilityCloakDemonstrated!".ComputingNews.2006.Retrieved2007-05-05. ^Yarris,Lynn(May1,2009)."BlurringtheLineBetweenMagicandScience:BerkeleyResearchersCreatean"InvisibilityCloak"".LawrenceBerkeleyNationalLaboratory.Retrieved2011-03-23. ^Valentine,Jason;Li,Jensen;Zentgraf,Thomas;Bartal,Guy;Zhang,Xiang(2009)."Anopticalcloakmadeofdielectrics"(PDF).NatureMaterials.8(7):568–71.arXiv:0904.3602.Bibcode:2009NatMa...8..568V.doi:10.1038/nmat2461.PMID 19404237.Archivedfromtheoriginal(PDF)on2011-10-07.Retrieved2011-03-23. ^Chen,Xianzhong;Luo,Yu;Zhang,Jingjing;Jiang,Kyle;Pendry,JohnB.;Zhang,Shuang(2011)."Macroscopicinvisibilitycloakingofvisiblelight".NatureCommunications.2(2):176.arXiv:1012.2783.Bibcode:2011NatCo...2E.176C.doi:10.1038/ncomms1176.PMC 3105339.PMID 21285954. ^Zhang,Baile;Luo,Yuan;Liu,Xiaogang;Barbastathis,George(2011)."MacroscopicInvisibilityCloakforVisibleLight".PhysicalReviewLetters.106(3):033901.arXiv:1012.2238.Bibcode:2011PhRvL.106c3901Z.doi:10.1103/PhysRevLett.106.033901.PMID 21405275.S2CID 13851653. ^"ScientistsDevelopNewInvisibilityCloakTechnology".redOrbit.April30,2009. ^Miller,DavidA.B.(2006)."Onperfectcloaking".OpticsExpress.14(25):12457–12466.Bibcode:2006OExpr..1412457M.doi:10.1364/OE.14.012457.PMID 19529679. Bibliography[edit] Stephens,Meic,ed.(1998).TheNewCompaniontotheLiteratureofWales.Cardiff:UniversityofWalesPress.ISBN 978-0-7083-1383-1. Furtherreading[edit] CloakingandInvisibility:FactandFictionbyProfessorDavidR.Smith-ElectricalandComputerEngineering-DukeUniversity(May28,2006) Three-dimensionalopticalmetamaterialwithanegativerefractiveindexbyJasonValentine,ShuangZhang,ThomasZentgraf,ErickUlin-Avila,DentchoA.Genov,GuyBartal,andXiangZhang.Natureadvanceonlinepublication11August2008. OpticalNegativeRefractioninBulkMetamaterialsofNanowiresbyJieYao,ZhaoweiLiu,YongminLiu,YuanWang,ChengSun,GuyBartal,AngelicaM.Stacy,andXiangZhang.Science15August2008:Vol.321.no.5891,p. 930. Leonhardt,Ulf;Smith,DavidR(2008)."FocusonCloakingandTransformationOptics".NewJournalofPhysics.10(11):115019.Bibcode:2008NJPh...10k5019L.doi:10.1088/1367-2630/10/11/115019. HidingarealisticobjectusingabroadbandterahertzinvisibilitycloakbyFanZhou,YongjunBao,WeiCao,ColinStuart,JianqiangGu,WeiliZhang,andChengSun.ScientificReports12011. Inami,M.;Kawakami,N.;Tachi,S.(2003)."Opticalcamouflageusingretro-reflectiveprojectiontechnology"(PDF).TheSecondIEEEandACMInternationalSymposiumonMixedandAugmentedReality,2003.Proceedings.pp. 348–349.CiteSeerX 10.1.1.105.4855.doi:10.1109/ISMAR.2003.1240754.ISBN 978-0-7695-2006-3.S2CID 44776407. Gonano,C.A.(2016).Aperspectiveonmetasurfaces,circuits,hologramsandinvisibility(PDF).PolitecnicodiMilano,Italy. Externallinks[edit] Vanishingpoint-TheGuardianInfoon"stealthsuit" InvisibilityCloakCreatedin3-D-BBCNews InvisibilityCloakOneStepCloser-BBCNews HowInvisibilityCloaksWork-HowStuffWorks Plasmonicinvisibilityeffect-LiveScience ScientistsAimtoDuplicateHarryPotter'sInvisibilityCloak-LiveScience Theinvisibilityasaresultof4DSEISfieldradiationeffect OnTheQuestToInvisibility-MetamaterialsandCloaking(video),Prof.AndreaAlùatTEDxAustin,2013. vteWitchcraftandmagicTypesRegion Africa Witchsmeller Asia Kulam Australasia Makutu Europe Akelarre Benandanti Chaosmagic Cunningfolk GreeceandRome Medieval Renaissance Seiðr Völva Whitewitch Witch-culthypothesis LatinAmerica Form Solitarypractitioner Warlock Wicca Witchdoctor Practices Animism Apotropaicmagic Blackmagic Ceremonialmagic Magicalformula Coven Demon Divination Entheogen Evocation Familiar Flyingointment Goetia Graymagic Jinn Lovemagic Magiccircle Magicword Mediumship Moonmagic Necromancy Occultism Poppet Potions Shamanism Black Yellow Regional Sigils Spiritism Spiritualism Sympatheticmagic Witchball Witch'sladder Witches'Sabbath Whitemagic Objects Amulet Broom besom Cloakofinvisibility Grimoire Kitchenwitch Lovecharm Magiccarpet Magicring Magicalweapons Magicsword Talisman Fulu YanshengCoin Wand Folkloreandmythology Agamede Aradia BabaYaga Dayan Drude Elbowwitch Huld Kalku Hecate Circe Medea MorganleFay MumaPădurii Ninesorceresses Obayifo Pasiphaë Seawitch Sebile Sorginak Spearfinger ThreeWitches WitchofEndor Historicalcase Anglo-SaxonEngland Britain Ghana Italy Majorhistorictreatises WitchcraftanddivinationintheOldTestament(8th–2ndcenturiesBC) DirectoriumInquisitorum(1376) Demaleficismulieribus(1440) Formicarius(1475) Summisdesiderantesaffectibus(1484) MalleusMaleficarum(1487) DeLamiisetPythonicisMulieribus(1489) Laienspiegel(1509) Depraestigiisdaemonum(1563) TheDiscoverieofWitchcraft(1584) NewesfromScotland(1591) ADialogueConcerningWitchesandWitchcrafts(1593) Daemonolatreiaelibritres(1595) Daemonologie(1597) MagicalInvestigations(1599) CompendiumMaleficarum(1608) AGuidetoGrand-JuryMen(1627) TheDiscoveryofWitches(1647) TreatiseontheApparitionsofSpiritsandonVampiresorRevenants(1751) Persecution Witch-hunt accusationsagainstchildren Inpopularculture Witchesinfiction Related Witch(word) Maleficium Left-handpathandright-handpath vteEmergingtechnologiesFieldsOther Anti-gravity Acousticlevitation Cloakofinvisibility Digitalscenttechnology Forcefield Plasmawindow Immersivevirtualreality Magneticrefrigeration Phased-arrayoptics Thermoacousticheatengine Category List Authoritycontrol:Nationallibraries Germany Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Cloak_of_invisibility&oldid=1082442222" Categories:ElectromagneticradiationFantasytropesRecurrentelementsinfairytalesInvisibilityMagicitemsFictionaboutinvisibilityRobesandcloaksEmergingtechnologiesHiddencategories:ArticleswithshortdescriptionShortdescriptionisdifferentfromWikidataArticlescontainingJapanese-languagetextArticlesneedingadditionalreferencesfromAugust2014AllarticlesneedingadditionalreferencesArticleswithGNDidentifiers Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Languages العربيةDeutsch한국어BahasaIndonesiaSvenskaไทยTürkçeУкраїнська Editlinks