Coherence - a ... coherent chiedza mafungu. rwepanyama coherence

Funga wave pakuwanza ari muchadenga. Coherence - mumwe nechiyero kuwirirana pakati maitikiro ayo, akayera panguva dzakasiyana pfungwa. Coherence chinozunguzirwa kunoenderana hunhu kwarwakabva.

Two Mhando coherence

Ngationei muenzaniso nyore. Fungidzira maviri ichiyangarara, ndichifumomuka uye kuwira pamusoro mvura pamusoro. Kufunga kuti wave panobva ndiyo chete tsvimbo iyo harmonically kunyudzwa uye kubviswa mvura nokuputsa wakagadzikana pemvura pamusoro. Saka pane akakwana kuwirirana pakati kufamba pakati floats maviri. Havagoni kwira uye pasi zvazviri kuyaruka, kana munhu achikwira, vamwe pasi, asi danho musiyano pakati nzvimbo yacho floats vaviri muupenyu nguva. Harmonically oscillating pfungwa panobva unobereka zvachose coherent wave.

Paanotsanangura coherence chechiedza nemafungu, kusiyanisa marudzi ayo maviri - spatial nezvenyama.

Coherence zvinoreva kukwanisa chiedza kubereka imwe chipingaidzo muenzaniso. Kana vaviri chiedza mafungu vanounzwa pamwechete, uye ivo havaumbi nzvimbo yakawedzera uye ungaderedza kupenya, dzinonzi incoherent. Kana ivo zvibereko "yakanaka" chipingaidzo muenzaniso (mupfungwa yakakwana rinoparadza chipingaidzo nzvimbo), dziri coherent. Kana mafungu mbiri kusika "zvishoma pane akakwana" mufananidzo, riri kuonekwa kuti vari aoma coherent.

Michelson interferometer

Coherence - kutanga kuti zvakanakisisa kutsanangurwa kumwe kuedza.

In Michelson interferometer chiedza kubva kupi S (izvo zvinogona chero: zuva, nyeredzi, kana Laser) chinotungamirwa mugomo semitransparent girazi M _0, rinomirira 50% of chiedza kune girazi M ₁ uye transmits 50% kune girazi M _2. Danda zvinoratidzwa kubva neimwe nezvionioni vakadzokera M _0, uye zvikamu zvakayenzana chiedza kwakaratidza kubva M ₁ uye M _{2 ikashandiswa} uye purojekita B. The mudziyo inogona configured nokuchinja daro kubva girazi M ₁ kusvika danda mahwanda.

Michelson interferometer chezvematongerwe mixes danda rine shanduro nguva-kunonoka yake. Light kuti inopfuura munzira kuenda mugirazi M ₁ rine kuenda kure pamusoro 2D kupfuura danda inobaya girazi M _2.

Kureba uye coherence nguva

Chii musi chidzitiro? Kana D = 0 anogona kuonekwa dzakawanda kwazvo zvakajeka chipingaidzo masa. Kana D rwuchiwanzwa, chisungo anova shoma raidudzwa: yerima nzvimbo chakajeka, uye chiedza - nokuda kwenhamo. Pakupedzisira, nokuti D guru chaizvo, zvikuru mumwe ukoshi dzakaoma D, chiedza nerima zvindori zvapfuura zvachose, kusiya chete akamhanya.

Zviri pachena, chiedza munda havagoni kuvhiringidza shanduro nguva-kunonoka pacharo kana nguva kunonoka yakakura zvakakwana. Distance 2D - ndiro coherence length: chipingaidzo Marwadzo kuoneka chete kana musiyano munzira isingasviki kure ichi. ukoshi Izvi zvinogona kuchinjwa mumakore t _C wayo weboka kubudikidza kumhanya chiedza d: t _C = 2D / c.

Michelson kuedza anoyera zvenyama coherence chechiedza chinozunguzirwa: kukwanisa yayo kupindira munhu kunonoka shanduro pacharo. A zvakanaka kudzikamiswa Laser t _C = 10 ^-4 s, L _C = 30 km; yakasvinwa chiedza kubva pakupisa T _C = 10 ^-8, L _C = 3 m.

Coherence uye nguva

Rwepanyama coherence - chiyero kuwirirana pakati maitikiro vechiedza waves zvakawanda pamwe Mashoko negwara.

Tambira bhuku inongorira wavelength pamusoro λ uye λ ± Δλ, izvo pane imwe nzvimbo uye kupindira chinhambwe L _C = λ ² / (2πΔλ). Apo k _C - coherence kureba.

The chehupenyu chokuninira pakuwanza ari X mirayiridzo richinzi add = Kx - ωt. Kana tikaongorora Figure mafungu nzvimbo panguva T nechokure L _c, Pasika musiyano pakati zviviri zvinozunguzirwa vectors K ₁ uye K _2, vari kuyaruka panguva x = 0 akaenzana Δφ = L _C (K ₁ - K _2). Apo Δφ = 1, kana Δφ ~ 60 °, chiedza hakuchina coherent. Chipingaidzo uye diffraction kuchikosha chaizvo kusiyana.

Saka:

• 1 = k _C (K ₁ - K _{2) = L C (2π / λ} - 2π / (λ + Δλ));
• _{k C (λ + Δλ - λ} ) / (λ (λ + Δλ)) ~ L C Δλ / λ ² = 1 / 2π;
• k _C = λ ² / (2πΔλ).

Wave ichipfuura nzvimbo ine velocity c.

The coherence nguva T _C = L _c / s. Sezvo λf = c, ipapo Δf / F = Δω / ω = Δλ / λ. Tinogona kunyora

• k _C = λ ² / (2πΔλ) = λf / ( 2πΔf) = c / Δω;
• zeva _C = 1 / Δω.

Kana anozivikanwa wavelength kana kakawanda Mashoko chiedza bhuku, zvinokwanisika kuverenga L _munenge uye t _c. Hazvibviri kuona kukanganiswa muenzaniso yaunganidzwa kugovera amplitude, akadai mutete firimu chipingaidzo, kana Manyiminya nzira musiyano zviri kupfuura L _c.

Rwepanyama coherence rinoti Black.

Coherence uye nzvimbo

Spatial coherence - chiyero kuwirirana pakati maitikiro vechiedza nemafungu siyana pfungwa transverse kutungamirirwa kupararira.

Kana kure L kubva monochromatic chafariz (Linear) panobva ane Linear kukura murayiro δ, ivo cheap car insurance maviri riri kure kupfuura D _C = 0,16λL / δ, hauchafambi pave kucherechedzwa chipingaidzo muenzaniso. πd _munenge ^2/4 ndiyo nzvimbo yacho coherence kunobva.

Kana panguva T kuona kunobva upamhi δ, dzinongoda perpendicular kure L kubva chidzitiro, chidzitiro anogona kuona mbiri pfungwa (p1 uye p2), akaparadzaniswa nevanhu kure d. The yemagetsi kusango p1 uye p2 anomiririra superposition electric kuminda mafungu chaibwinya vose pfungwa kunobva, nokuita kuti mwaranzi usingagoni zvakabatana nepedyo. To remagetsi mafungu exiting p1 uye p2, kutanga kucherechedzwa chipingaidzo muenzaniso superposition p1 uye p2 zvinofanira kuyaruka.

coherence ezvinhu

Light mafungu airatidza ne miviri yehombodo kunobva, pane imwe nguva nguva T vane imwe danho musiyano zvakananga pakati pakati mbiri pfungwa. Danda kuuya kubva kuruboshwe kumucheto δ kuchinhu p2 kupfuudza D (sinθ) / 2 kure kupfuura danda vaienda pakati. The trajectory of danda richibva rworudyi kumucheto δ kukuratidza p2, anoudzawo D nzira (sinθ) / 2 zvishoma. The musiyano kure vakafamba matanda maviri d · sinθ uye inomiririra Pasika musiyano Δf '= 2πd · sinθ / λ. Nokuti kure p1 kuna p2 pamwe chinozunguzirwa pamberi, tinowana Δφ = 2Δφ '= 4πd · sinθ / λ. Mafungu chaibwinya ne miviri yehombodo kunobva, vari kuyaruka pamwe p1 panguva T uye vari kubva danho munzvimbo 4πdsinθ / λ muna p2. Sezvo sinθ ~ δ / (2L), ipapo Δφ = 2πdδ / (Lλ). Apo Δφ = Δφ ~ 1 kana 60 °, chiedza haasisina vaiona coherent.

Δφ = 1 -> D = Lλ / (2πδ) = 0,16 Lλ / δ.

The spatial coherence pamusoro akati wavefront kutotanga homogeneity.

Incandescent rambi muenzaniso incoherent chiedza kunobva.

chiedza Coherent kunogona kuwanikwa kubva kunobva incoherent mwaranzi, kana isu kurasa zhinji mwaranzi. Yokutanga spatial mupise rinoitwa kuwedzera spatial coherence, uye ipapo spectral mupise kuti hombe rwepanyama coherence.

Fourier dzino

Sinusoidal ndege chinozunguzirwa coherent zvachose muchadenga uye nenguva, uye kureba kwenguva uye coherence nzvimbo kusingaperi. All mafungu chaivo vari chinozunguzirwa pulses nokusingagumi imwe finite nguva chinguva, uye ndine magumo perpendicular dzavo zvataurwa kupararira. Mathematically, vanorondedzerwa ne kwenguva nenguva basa. Kuti tiwane frequencies aripo chinozunguzirwa pulses uye kuona munhu coherence urefu Δω vanofanira kuongorora non-Periodic mabasa.

Maererano Fourier pachisara imwe zvemasanga nguva nenguva chinozunguzirwa inogona anoonekwa somunhu superposition of Sine nemafungu. Fourier usage zvinoreva kuti superposition ane muzvizhinji kuti sinusoidal mafungu inobvumira kuwana zvemasanga nguva nenguva waveform.

Communication nhamba

Coherence dzidziso anogona kunzi sezvo kubatana kwakaita wefizikisi sayenzi vamwe, sezvo mugumisiro kwemapazi pakati remagetsi pfungwa uye nhamba, uyewo Statistical hurongwa mubatanidzwa wenyika nhamba hurongwa. Fungidziro rinoshandiswa uwandu hwazvo unhu uye migumisiro anongoitika nokufamba nomufambiro minda chiedza.

Kazhinji hazvibviri kuyera nokufamba musango chinozunguzirwa zvakananga. Munhu "nemateru nezvisingafadzi" chiedza chinoonekwa haigoni kuonekwa zvakananga, kana kunyange akaoma zviridzwa: kwayo maitikiro iri anenge October oscillations ¹⁵ pasekondi yoga yoga. Unogona chete kuyera Avharenji.

Kushandiswa coherence

Connection kuti Physics sayenzi vamwe muenzaniso coherence kunogona kurondwa mune dzinoverengeka mafomu. Aoma minda coherent havanyanyi kukanganiswa mumhepo mhirizhonga, izvo zvinoita kuti anobatsira Laser kukurukurirana. Vanewo anoshandiswa kudzidza Laser Kutemeswa Fusion siyana: zvinoderedza kuti kukanganiswa migumisiro kunotungamirira "chechetere" Zvakaitwa danda riri yenyukireya chipfuro. Coherence inoshandiswa kunyanya kuona kukura uye hurumende ichiisa nenyeredzi binary gadziriro.

Coherence chiedza mafungu inoita basa rinokosha iri kudzidza quantum uye chekare minda. Muna 2005, Roy J. Glauber akava mumwe vakundi Nobel Prize muna Physics kuti mupiro wake quantum dzidziso Manyiminya coherence.