Laser txoj cai thiab nws daim ntawv thov

Laser hais txog cov txheej txheem thiab cov cuab yeej ntawm kev tsim cov teeb pom kev sib txuas, monochromatic, coherent teeb kab teeb los ntawm kev txhawb nqa hluav taws xob ua kom muaj zog thiab cov lus qhia tsim nyog. Yeej, laser tiam yuav tsum muaj peb lub ntsiab lus: "resonator," "tau txais nruab nrab," thiab "tswj qhov chaw."

A. Txoj Cai

Lub zog ntawm lub atom tuaj yeem muab faib ua ntau theem ntawm lub zog, thiab thaum lub atom hloov pauv ntawm lub zog siab mus rau qib qis zog, nws tso tawm photons ntawm lub zog sib xws (hu ua hluav taws xob spontaneous ). Ib yam li ntawd, thaum lub photon tshwm sim nyob rau hauv lub zog theem system thiab absorbed los ntawm nws, nws yuav ua rau lub atom hloov los ntawm ib tug tsawg zog theem mus rau ib tug siab zog (tseem hu ua zoo siab absorption); Tom qab ntawd, qee cov atoms uas hloov mus rau qib siab zog yuav hloov mus rau qis zog thiab emit photons (hu ua hluav taws xob txhawb zog). Cov kev txav no tsis tshwm sim hauv kev sib cais, tab sis feem ntau ua ke. Thaum peb tsim ib qho kev mob, xws li siv qhov nruab nrab tsim nyog, resonator, txaus sab nraud hluav taws xob, cov hluav taws xob tsim hluav taws xob yog amplified kom ntau tshaj qhov kev nqus nqus nqus, feem ntau, yuav muaj photons tawm, ua rau lub teeb laser.

B. Kev faib tawm

Raws li qhov nruab nrab uas tsim cov laser, lub laser yuav muab faib ua kua laser, roj laser thiab khoom laser. Tam sim no qhov ntau tshaj plaws semiconductor laser yog ib hom ntawm solid-state laser.

C. Kev sib xyaw

Feem ntau cov lasers yog tsim los ntawm peb qhov chaw: excitation system, laser khoom thiab optical resonator. Excitation systems yog cov khoom siv uas tsim lub teeb, hluav taws xob lossis tshuaj lom neeg lub zog. Tam sim no, qhov kev txhawb siab tseem ceeb uas siv yog lub teeb, hluav taws xob lossis tshuaj lom neeg cov tshuaj tiv thaiv. Cov khoom siv laser yog cov khoom uas tuaj yeem tsim lub teeb laser, xws li rubies, beryllium iav, neon gas, semiconductors, organic dyes, thiab lwm yam. Lub luag haujlwm ntawm optical resonance tswj yog txhawm rau txhim kho qhov ci ntawm cov zis laser, kho thiab xaiv lub wavelength thiab kev taw qhia. ntawm lub laser.

D. Daim ntawv thov

Laser yog dav siv, feem ntau fiber ntau kev sib txuas lus, laser ntau, laser txiav, laser riam phom, laser disc thiab hais txog.

E. Keeb kwm

Xyoo 1958, Asmeskas cov kws tshawb fawb Xiaoluo thiab Townes tau tshawb pom qhov tshwm sim tej yam yees siv: thaum lawv muab lub teeb tawm los ntawm lub teeb sab hauv ntawm lub ntiaj teb tsis tshua muaj siv lead ua, cov molecules ntawm cov siv lead ua yuav emit ci ntsa iab, ib txwm ua ke lub teeb muaj zog. Raws li qhov tshwm sim no, lawv tau hais txog "laser txoj cai", uas yog, thaum cov khoom zoo siab los ntawm tib lub zog raws li lub ntuj oscillation zaus ntawm nws cov molecules, nws yuav tsim lub teeb muaj zog uas tsis sib txawv - laser. Lawv nrhiav tau cov ntaub ntawv tseem ceeb rau qhov no.

Tom qab luam tawm ntawm Sciolo thiab Townes cov txiaj ntsig kev tshawb fawb, cov kws tshawb fawb los ntawm ntau lub teb chaws tau npaj ntau yam kev sim, tab sis lawv tsis ua tiav. Thaum lub Tsib Hlis 15, 1960, Mayman, tus kws tshawb fawb ntawm Hughes Laboratory hauv California tau tshaj tawm tias nws tau txais lub laser nrog lub wavelength ntawm 0.6943 microns, uas yog thawj laser puas tau los ntawm tib neeg, thiab Mayman yog li ntawd los ua thawj tus kws tshawb fawb hauv ntiaj teb. los qhia lasers rau hauv cov tswv yim teb.

Thaum Lub Xya Hli 7, 1960, Mayman tshaj tawm hnub yug ntawm lub ntiaj teb thawj lub laser, Mayman lub tswv yim yog siv lub siab siv lub teeb nyem los txhawb cov chromium atoms nyob rau hauv lub ruby ​​siv lead ua, yog li tsim ib lub teeb liab nyias nyias, thaum nws raug rho tawm haujlwm. ntawm ib qho chaw, nws tuaj yeem ncav cuag qhov kub siab tshaj qhov saum npoo ntawm lub hnub.

Tus kws tshawb fawb Soviet H.Γ Basov tau tsim lub tshuab hluav taws xob semiconductor hauv xyoo 1960. Cov qauv ntawm semiconductor laser feem ntau yog tsim los ntawm P txheej, N txheej thiab cov txheej txheem ua haujlwm uas tsim ob npaug heterojunction. Nws cov yam ntxwv yog: me me, siab coupling efficiency, ceev teb ceev, wavelength thiab loj haum nrog optical fiber ntau, tuaj yeem hloov kho ncaj qha, zoo coherence.

Rau, qee qhov tseem ceeb ntawm daim ntawv thov kev qhia ntawm laser

F. Laser kev sib txuas lus

Kev siv lub teeb los xa cov ntaub ntawv muaj ntau heev niaj hnub no. Piv txwv li, cov nkoj siv teeb pom kev sib txuas lus, thiab teeb pom kev tsheb siv liab, daj, thiab ntsuab. Tab sis txhua txoj hauv kev ntawm kev xa cov ntaub ntawv siv lub teeb pom kev zoo tsuas yog txwv rau qhov kev ncua deb. Yog tias koj xav xa cov ntaub ntawv ncaj qha mus rau qhov chaw nyob deb ntawm lub teeb, koj tsis tuaj yeem siv lub teeb pom kev zoo, tab sis tsuas yog siv lasers.

Yog li cas koj xa lub laser? Peb paub tias hluav taws xob tuaj yeem nqa tau raws li cov xov tooj hlau, tab sis lub teeb tsis tuaj yeem nqa nrog cov hlau zoo tib yam. Txog rau qhov kawg no, cov kws tshawb fawb tau tsim cov filament uas tuaj yeem xa lub teeb, hu ua optical fiber, hu ua fiber. Optical fiber ntau yog ua los ntawm cov khoom siv iav tshwj xeeb, txoj kab uas hla yog nyias dua li tib neeg cov plaub hau, feem ntau yog 50 txog 150 microns, thiab mos heev.

Qhov tseeb, lub hauv paus tseem ceeb ntawm cov fiber ntau yog lub siab refractive index ntawm pob tshab optical iav, thiab txheej txheej yog ua los ntawm cov iav tsis tshua muaj refractive index iav los yog yas. Xws li cov qauv, ntawm ib sab, tuaj yeem ua rau lub teeb refracted raws lub hauv paus ntsiab lus, ib yam li cov dej ntws mus rau hauv cov yeeb nkab dej, hluav taws xob xa mus rau pem hauv ntej ntawm cov hlau, txawm tias ntau txhiab twists thiab lem tsis muaj txiaj ntsig. Ntawm qhov tod tes, qhov qis-refractive index txheej txheej tuaj yeem tiv thaiv lub teeb los ntawm kev xau tawm, ib yam li cov yeeb nkab dej tsis nkag thiab cov txheej rwb thaiv tsev ntawm cov hlau tsis muaj hluav taws xob.

Cov tsos ntawm optical fiber daws txoj kev xa lub teeb, tab sis nws tsis txhais hais tias nrog nws, txhua lub teeb tuaj yeem xa mus rau qhov deb heev. Tsuas yog lub teeb ci siab, xim ntshiab, zoo taw qhia laser, yog lub teeb pom kev zoo tshaj plaws los xa cov ntaub ntawv, nws yog cov tswv yim los ntawm ib qho kawg ntawm fiber ntau, yuav luag tsis muaj kev poob thiab tawm ntawm lwm qhov kawg. Yog li ntawd, kev sib txuas lus kho qhov muag yog qhov tseem ceeb ntawm kev sib txuas lus laser, uas muaj qhov zoo ntawm lub peev xwm loj, zoo siab, dav ntawm cov ntaub ntawv, muaj zog tsis pub lwm tus paub, durability, thiab lwm yam, thiab tau qhuas los ntawm cov kws tshawb fawb raws li kev hloov pauv hauv kev sib txuas lus, thiab yog ib qho. ntawm qhov ua tau zoo tshaj plaws hauv kev hloov kho thev naus laus zis.