Lub Cim ntawm Lasers

Lub Cim ntawm Lasers
Lub cim ntawm lasers tau raug tsim los ntawm Einstein hauv xyoo 1916 nrog nws txoj kev xav ntawm "kev tso tawm sai thiab kev txhawb nqa". Txoj kev xav no tsim lub hauv paus ntawm lub cev ntawm cov tshuab laser niaj hnub. Kev sib cuam tshuam ntawm photons thiab atoms yuav ua rau peb txoj kev hloov pauv: kev nqus tau txais, kev tso tawm sai, thiab kev tso tawm. Tsuav yog kev tso tawm tau txais thiab ruaj khov, lasers tuaj yeem tau txais. Yog li ntawd, cov khoom siv tshwj xeeb - lasers - yuav tsum tau tsim. Cov khoom sib xyaw ntawm laser feem ntau yog tsim los ntawm peb qhov tseem ceeb: cov khoom siv ua haujlwm, cov khoom siv txhawb nqa, thiab lub teeb pom kev zoo.

1. Cov khoom ua haujlwm

Cov khoom hauv lub laser uas tuaj yeem tsim lub teeb laser hu ua cov khoom ua haujlwm. Nyob rau hauv qhov xwm txheej ib txwm muaj, kev faib tawm ntawm cov lej atomic hauv cov khoom ntawm txhua qib zog yog qhov faib tawm ib txwm muaj. Tus naj npawb ntawm cov atoms ntawm qib zog qis dua yeej ib txwm ntau dua li ntawm qib zog siab dua. Yog li ntawd, thaum lub teeb hla dhau lub xeev ib txwm muaj ntawm cov khoom luminescent, cov txheej txheem nqus yog dominant, thiab lub teeb ib txwm tsis muaj zog. Txhawm rau ua kom lub teeb muaj zog tom qab dhau los ntawm cov khoom luminescent thiab ua tiav lub teeb amplification, nws yog qhov tsim nyog los ua kom stimulated emission dominant. Txhawm rau ua kom tus naj npawb ntawm cov atoms ntawm qib zog siab dua li ntawm qib zog qis dua, qhov kev faib tawm no yog qhov sib txawv ntawm kev faib tawm ib txwm muaj thiab hu ua tus lej particle inversion.
2. Kev Txhawb Nqa
Lub luag haujlwm ntawm lub cuab yeej excitation yog ua kom cov atoms nyob rau hauv qib qis zog mus rau qib siab zog, ua rau cov khoom ua haujlwm ua tiav qhov kev hloov pauv ntawm cov lej particle. Cov qib zog ntawm cov khoom suav nrog lub xeev av thiab lub xeev excited, nrog rau lub xeev metastable. Lub xeev metastable tsis ruaj khov dua li lub xeev av, tab sis ruaj khov dua li lub xeev excited. Hais lus piv txwv, cov atoms tuaj yeem nyob hauv lub xeev metastable rau lub sijhawm ntev dua. Piv txwv li, cov chromium ions (Cr3 +) hauv ruby ​​​​muaj lub xeev metastable nrog lub neej ntawm qhov kev txiav txim ntawm 10-3 vib nas this. Tom qab cov khoom ua haujlwm raug excited thiab ua tiav qhov kev hloov pauv ntawm cov lej particle, thawj zaug, vim yog cov lus qhia sib txawv ntawm cov photons uas tso tawm los ntawm kev tawg spontaneous, cov photons hluav taws xob stimulated kuj muaj cov lus qhia sib txawv, thiab muaj ntau qhov poob hauv cov zis thiab kev nqus; cov zis laser ruaj khov tsis tuaj yeem tsim tau. Yuav kom cov hluav taws xob stimulated txuas ntxiv mus nyob hauv qhov ntim tsawg ntawm cov khoom ua haujlwm, xav tau lub resonator optical kom ua tiav kev xaiv thiab kev ua kom lub teeb ci ntsa iab.
3. Lub tshuab kho qhov muag
Nws yog ib khub daim iav uas sib luag sib luag, ntsia rau ob sab kawg ntawm cov khoom siv ua haujlwm, perpendicular rau lub axis tseem ceeb. Ib kawg yog daim iav tag nrho (nrog rau tus nqi cuam tshuam ntawm 100%), thiab lwm qhov kawg yog daim iav pob tshab thiab ib nrab cuam tshuam (nrog rau tus nqi cuam tshuam ntawm 90% txog 99%).
Lub luag haujlwm ntawm lub resonator yog: ① tsim thiab tswj kev ua kom pom kev zoo; ② xaiv qhov kev taw qhia ntawm lub teeb tso zis; ③ xaiv qhov wavelength ntawm lub teeb tso zis. Rau ib qho khoom ua haujlwm tshwj xeeb, vim muaj ntau yam, qhov wavelength ntawm lub teeb tso tawm tiag tiag tsis yog qhov tshwj xeeb, thiab lub spectrum muaj qhov dav. Lub resonator tuaj yeem ua lub luag haujlwm xaiv zaus, ua rau lub monochromaticity ntawm lub laser zoo dua.