Kungani Fresnel zone

Fresnel zone - kukhona izindawo kulo kobuso umsindo noma ukukhanya amagagasi lokufeza izibalo Imiphumela umumo womsebenzi umsindo noma ukukhanya. Le ndlela lasetshenziswa kuqala ku 1815 O.Frenel.

Imininingwane zomlando

Augustin-Zhan Frenel (10.06.1788-14.07.1827) - physics French. Yena wanikela ukuphila kwakhe ukutadisha izakhiwo yokukhanya ngokomzimba. Wabuye e 1811 ngaphansi kwethonya E. malus waqala ngokuzimela ukufunda physics, ngokushesha waqala ukuba nesithakazelo ucwaningo zokuhlola emkhakheni yokukhanya. Ngo 1814, i- "balithola" isimiso kwezithikamezo, futhi ngo-1816 ungeze isimiso owaziwa Huygens, eyethula umqondo kuhambelana nekuhlangana ukuphazamiseka ngamagagasi aphansi. Ngo 1818, sakhela phezu umsebenzi, wahlakulela imfundiso yokuziphendukela ka umumo womsebenzi ukukhanya. Wethula umkhuba zokucutshungulwa umumo womsebenzi kusukwa, kanye umgodi isiyingi. ucwaningo olwenziwa, manje zabuna, ne biprism futhi bizerkalami ukugxambukela ukukhanya. Ngo 1821 ayebonisa yokuthi yesimo transverse ngamagagasi ukukhanya, ngo-1823 wavula nokwehlukana isiyingi futhi okweqanda. Wachaza ngesisekelo wave izethulo nokwehlukana chromatique, kanye ukujikeleza indiza ka nokwehlukana ukukhanya futhi birefringence. Ngo-1823, wasungula imithetho kwalungiswa izinkunga zokubona futhi ibonisa ukukhanya phezu esinqunyiwe surface flat phakathi kwabezindaba ezimbili. Kanye Jung kubhekwe ungumdali wave yokukhanya. Ingabe umsunguli amadivayisi ukuphazamiseka eminingana, njengethi nesibuko noma Fresnel biprism Fresnel. It kubhekwa umsunguli ngendlela ngokuyinhloko entsha yesibani okukhanyisa.

Nasi theory

Nquma Fresnel umumo womsebenzi kungenzeka umgodi yanoma iluphi futhi ngokuvamile ngaphandle kwalo. Nokho, kusukela iphuzu Ngenxa abheke ukuthi kungenzeka kungcono aphathe it in isiyingi imbobo ukuma. Kulokhu, umthombo wokukhanya kanye nokuqaphelisisa iphuzu kumelwe libe umugqa okungukuthi perpendicular indiza isikrini bese sidlula maphakathi imbobo. Eqinisweni, ezonini Fresnel naphula iyiphi indawo lapho amaza okukhanya. Ngokwesibonelo, ebusweni equiphase. Nokho, kulesi simo-ke kuyoba lula ukuba aphule flat zone imbobo. Ngenxa yalesi sicabanga izinkinga aphansi optical, okuyokwenza ukuba sithole engaba Fresnel zone kuqala hhayi kuphela, kodwa futhi ukulandelelwa izinombolo okungahleliwe.

Umsebenzi yokunquma Usayizi izindandatho

Ukuze uqale ukucabanga ukuthi kobuso imbobo uyisicaba phakathi umthombo wokukhanya (iphuzu C) kanye ingqapheli (iphuzu H). Kuyinto perpendicular umugqa CH. CH ingxenye sidlula round imbobo isikhungo (iphuzu O). Njengoba umgomo wethu eksisi wesimethri, le Fresnel zone kuyoba ngesimo izindandatho. Isinqumo kuzoncishiswa ukuzimisela engaba mibuthano nge nenombolo engafanele (m). Inani esiphezulu ibizwa ngokuthi lo engaba zone. Ukuze kuxazululwe le nkinga kubalulekile ukwenza ukwakhiwa ezengeziwe, okuyilezi: ukhethe iphoyinti ngokungenasizathu (A) endizeni kuvulwa bese uxhuma umugqa izingxenye ngokuqondile kusukela iphuzu observation umthombo wokukhanya. Imiphumela iba yinhlanganisela yokukhandleka SAN unxantathu. Khona-ke ungenza ukuze wave ukukhanya ezifika umuntu obuka endleleni we SAN, ukudlula indlela eside kunaleso obukade izothatha CH endleleni. Lokhu kusho ukuthi i-CA indlela umehluko + AN-CH ichaza umehluko phakathi izigaba wave ziyadlula ezivela emithonjeni yesibili (A no D) endaweni observation. Kule ukubaluleka kuncike nomphumela amagagasi ukuphazamisa isikhundla obuka, futhi kungakho umfutho ukukhanya ngaleso sikhathi.

Ukubalwa engaba lokuqala

Sithola ukuthi uma umehluko endleleni ilingana isigamu nombono ukukhanya (λ / 2), ukukhanya eza obuka e antiphase. It lingahunyushwa baphetha ukuthi uma umehluko endleleni kuyoba esingaphansi λ / 2, ukukhanya kuyofika esigabeni esifanayo. Lokhu CA isimo + AN-SN≤ λ / 2, nge ncazelo, isimo ukuthi iphuzu A itholakala iringi lokuqala, isb kuba Fresnel zone kuqala. Kulokhu, umngcele umehluko umbuthano endleleni ilingana isigamu nombono yokukhanya. Ngakho lokhu kwesibalo ukucacisa engaba indawo yokuqala, okhonjiswe P _1. Lapho umehluko endleleni elihambisana λ / 2, kuyoba ilingane ingxenye OA. Kuleso simo, uma amabanga idlule kakhulu CO imbobo ubukhulu (ngokuvamisile kubhekwe embodiments nje enjalo), i-ngokucabangisisa engaba weJiyomethri zone lokuqala ebizwa ngokuthi le ndlela elandelayo: P ₁ = √ (λ * CO + OH) / (CO + OH).

Ukubalwa engaba Fresnel zone

Formula sokunquma abakuzuzile radii izindandatho okwalandela ayafana okuxoxwe ngazo ngenhla, kumane kungezelela numerator yenomboro zone oyifunayo. Kuleso simo nokulingana indlela umehluko uba: CA + AN-SN≤ m * λ / 2 noma CA + AH-CO-ON≤ m * λ / 2. Lokho kusho ukuthi lo engaba endaweni oyifunayo nenani "m" ichaza fomula elandelayo: P _m = √ (m * λ * CO + OH) / (CO + OH) = ₁ P √m

Efingqa imiphumela ephakathi nendawo

Kungaphawulwa ukuthi zone kuphulwa - ukwehlukana secondary umthombo wokukhanya ukuba segezi kokuba endaweni efanayo, njengoba _m n = π * R ² _m - π * R ² _m-1 = π * ₁ P ² = P _1. Ukukhanya okuvela engumakhelwane Fresnel esishintshashintshayo iza isigaba okuphambene, ngoba indlela umehluko emasongweni ezingomakhelwane definition ulingana isigamu nombono yokukhanya. Generalizing lomphumela, siphetha ngokuthi ekuhlephuleni izimbobo imbuthano (yokuthi ukukhanya okuvela angomakhelwane ifinyelela obuka nge engaguquki isigaba umehluko) kwakuzosho breaking iringi endaweni efanayo. Lokhu ukugomela is kalula wafakazela ngosizo inkinga.

zone Fresnel okwesikhathi wave indiza

Cabanga ukuwohloka ukuvula indawo ku izindandatho ohlabayo endaweni alinganayo. Lezi Imibuthano ukukhanya imithombo. I amplitude we ukukhanya wave ukufika kusuka indandatho ngamunye umuntu obuka, cishe okufanayo. Ngaphezu kwalokho, umehluko isigaba kusukela uhla eduze ngesikhathi H phuzu ubuye okufanayo. Kulokhu, lo amplitudes eziyinkimbinkimbi ngesikhathi obuka lapho kungezwe olulodwa eziyinkimbinkimbi ifomu indiza ingxenye umbuthano - arc. Inani amplitude okufanayo - kuzithinta. Manje cabanga ngalokho okushiwo iphethini nokushintsha summation amplitude uma ushintsho engaba imbobo ebe egcina nemingcele yenkinga. Kuleso simo, uma imbobo kuvula indawo eyodwa kuphela obuka, iphethini ngokungeza ingxenye inikezwe circumferentially. I amplitude we ring zokugcina ijikeleziswa ngu isihlobo engela π ephakathi okuyingxenye, isb. K. Indlela umehluko we zone wokuqala, nge ncazelo, ilingana λ / 2. Lokhu engela uzobe π kusho amplitude kuyoba ingxenye selilonke. Kulokhu, isamba lezi zimiso endaweni eyakusho zero - zero kuzithinta obuphelele. Uma izindandatho ezintathu eyovulwa ke isithombe ngeke amele umbuthano isigamu nokunye. I amplitude e iphuzu obuka ngayo i ngisho inani izindandatho zero. Futhi endabeni uma usebenzisa inombolo obungavamile imibuthano, kuyoba ulingana seqiwe nobude ububanzi indiza eyinkimbinkimbi kwalokho amplitudes. Izinjongo kokungaphezulu ngokugcwele indlela evulekile Fresnel esishintshashintshayo.

Kafushane mayelana ezithile

Cabangela izimo ezingavamile. Ngezinye izikhathi, ukuxazulula uthi inkinga usebenzisa izinombolo ayingxenye ye Fresnel esishintshashintshayo. Kulokhu, ngaphansi ring isigamu bona iphethini ikota mbuthano, okuzokwenza zivumelana uhhafu endaweni indawo yokuqala. Ngokufanayo ibalwa yimuphi omunye ukubaluleka wamaqhuzu. Ngezinye izikhathi isimo kusikisela ukuthi inani elithile wamaqhuzu izindandatho ivaliwe kanye nokunye evulekile. Esimweni esinjalo, amplitude ingqikithi vector ensimini kutholakala njengoba umehluko we amplitudes imisebenzi emibili. Lapho zonke izingxenye zivuliwe, khona-ke alikho isithiyo endleleni amaza okukhanya, isithombe izobukeka Kuvunguza. It kuvela, ngoba uma uvula inqwaba Amasongo kufanele acabangele ukwencika ekushayweni umthombo wokukhanya kuze kube seqophelweni ingqapheli kanye isiqondiso umthombo yesibili. Sithola ukuthi ukukhanya okuvela zone ngenombolo ephakeme has a amplitude amancane. Centre Helix etholakala kule selilonke phakathi izindandatho lokuqala nelesibili. Ngakho-ke, lo amplitude ensimini esimweni lapho bonke endaweni ebonakalayo lingaphansi kuka kabili kunangesikhathi evulekile eyodwa disk lokuqala, futhi umfutho kuyahluka kane.

Fresnel umumo womsebenzi ukukhanya

Ake sibheke ukuthi kushiwoni leli gama. Ngokuthi isimo umumo womsebenzi Fresnel, lapho ngembobo kuvula ezindaweni eziningana. Uma sizovula eningi izindandatho, le ndlela-ke kungenziwa indiva, ukuthi bafakela ku isilinganiselo ukuze yokukhanya yejeyomethri. Esimweni lapho emgodini ngokusebenzisa ivulekile obuka kakhulu esingaphansi zone, kulesi simo sibizwa ngokuthi Fraunhofer umumo womsebenzi. He kubhekwa yaneliswe uma umthombo wokukhanya kanye iphuzu obuka kukhona buqamama eyanele kusukela imbobo.

Ukuqhathanisa lens zone ipuleti

Uma uvala zonke lingalingani noma zonke indawo ngisho Fresnel, kuyilapho ngesikhathi obuka iyona wave ukukhanya nge amplitude enkulu. Ngamunye indandatho indiza eziyinkimbinkimbi unika umbuthano nengxenye. Ngakho uma wangasho izingxenye lingalingani ke inani ngeke kuphela Kuvunguza neengcezu emibuthano, ezinomthelela amplitude jikelele "phansi-up". Inkinga endleleni igagasi ukukhanya, lapho uhlobo olulodwa kuphela izindandatho evulekile, ngokuthi ipuleti zone. Amandla ukukhanya obuka ngokuphindaphindiwe idlule ukushuba ukukhanya phezu plate. Lokhu kungenxa yokuthi leli gagasi ukukhanya indandatho ngamunye evulekile simakhiwe umuntu obuka esigabeni esifanayo.

Namuhla kunesimo esithi asifane siyenzeka nge ngokugxila ukukhanya nge lens. It, ngokungafani amapuleti, akukho izindandatho kungukuthi ivaliwe, futhi ushukumisela ukukhanya isigaba ngu π * (+ 2 π * m) kusuka nemibuthano ivaliwe ipuleti zone. Ngenxa yalokho, lo amplitude we wave ukukhanya kabili. Ngaphezu kwalokho, i-lens aqede okuthiwa okuhambisanayo isigaba ukuqhela okuyizinto ngaphakathi indandatho eyodwa. It uyenaba indiza eyinkimbinkimbi selilonke nengxenye zone ngalinye ngendlela eqondile umugqa ingxenye. Ngenxa yalokho, ukwanda amplitude by izikhathi π, futhi lonke eziyinkimbinkimbi indiza Kuvunguza lens zisashisa ku umugqa oqondile.