Niaj hnub no, peb yuav qhia ib tug "monochromatic" laser mus rau qhov kawg - nqaim linewidth laser. Nws tshwm sim nyob rau hauv ntau qhov chaw ntawm daim ntawv thov laser, thiab nyob rau hauv xyoo tas los no tau dav siv nyob rau hauv gravitational yoj nrhiav kom tau, liDAR, faib sensing, high-speed coherent optical kev sib txuas lus thiab lwm yam teb, uas yog ib tug "lub hom phiaj" uas tsis tuaj yeem ua tau. ua tiav tsuas yog los ntawm kev txhim kho lub zog laser.
Dab tsi yog qhov nqaim linewidth laser?
Lub sij hawm "kab dav" yog hais txog spectral kab dav ntawm lub laser nyob rau hauv lub zaus sau, uas feem ntau yog quantified nyob rau hauv cov nqe lus ntawm ib nrab-peak tag nrho dav ntawm lub spectrum (FWHM). Lub linewidth feem ntau cuam tshuam los ntawm cov hluav taws xob tshwm sim ntawm cov atoms lossis ions, theem suab nrov, kev vibration ntawm lub resonator, kub jitter thiab lwm yam sab nraud. Qhov me dua tus nqi ntawm txoj kab dav, qhov siab dua qhov purity ntawm lub spectrum, uas yog, qhov zoo dua qhov monochromaticity ntawm lub laser. Lasers nrog cov yam ntxwv zoo li no feem ntau muaj me ntsis theem lossis lub suab nrov nrov thiab cov suab nrov ntawm cov txheeb ze tsawg heev. Nyob rau tib lub sijhawm, qhov me me ntawm cov kab dav dav ntawm lub laser, qhov muaj zog dua qhov sib txuam, uas yog manifested raws li qhov ntev coherence ntev heev.
Realization thiab daim ntawv thov ntawm nqaim linewidth laser
Txwv tsis pub los ntawm qhov kev nce hauv linewidth ntawm cov khoom ua haujlwm ntawm lub laser, nws yuav luag tsis yooj yim sua kom paub ncaj qha cov zis ntawm nqaim linewidth laser los ntawm kev cia siab rau cov tsoos oscillator nws tus kheej. Txhawm rau kom paub txog kev ua haujlwm ntawm nqaim linewidth laser, feem ntau nws yog qhov yuav tsum tau siv cov ntxaij lim dej, grating thiab lwm yam khoom siv los txwv lossis xaiv qhov longitudinal modulus hauv qhov nce spectrum, ua kom cov txiaj ntsig nce qhov sib txawv ntawm cov qauv longitudinal, thiaj li muaj qhov sib txawv. ob peb lossis txawm tias tsuas yog ib hom longitudinal oscillation hauv laser resonator. Nyob rau hauv cov txheej txheem no, nws yog ib qho tsim nyog los tswj cov suab nrov ntawm lub laser tso zis, thiab txo qhov kev nthuav dav ntawm cov kab spectral tshwm sim los ntawm kev vibration thiab kub hloov ntawm qhov chaw sab nraud; Nyob rau tib lub sijhawm, nws tseem tuaj yeem ua ke nrog kev tsom xam ntawm theem lossis zaus lub suab nrov spectral ceev kom nkag siab txog lub hauv paus ntawm lub suab nrov thiab ua kom zoo dua qhov tsim ntawm lub laser, thiaj li ua tiav cov txiaj ntsig ruaj khov ntawm qhov nqaim linewidth laser.
Cia wb mus saib qhov kev ua tiav ntawm txoj haujlwm nqaim ntawm ob peb pawg sib txawv ntawm lasers.
Semiconductor lasers muaj qhov zoo ntawm qhov loj me, kev ua haujlwm siab, lub neej ntev thiab cov txiaj ntsig kev lag luam.
Fabry-Perot (FP) optical resonator siv nyob rau hauv ib txwmsemiconductor lasersfeem ntau oscillates nyob rau hauv multi-longitudinal hom, thiab cov zis kab dav dav yog qhov dav, yog li nws yog ib qho tsim nyog yuav tsum tau ua kom cov kev tawm tswv yim kho qhov muag kom tau txais cov zis ntawm txoj kab nqaim dav.
Distributed feedback (DFB) thiab Distributed Bragg reflection (DBR) yog ob qho tib si sab hauv kho qhov muag tawm tswv yim semiconductor lasers. Vim lub me me grating pitch thiab zoo wavelength selectivity, nws yog ib qho yooj yim mus cuag ruaj khov ib zaus nqaim linewidth tso zis. Qhov sib txawv tseem ceeb ntawm ob lub qauv yog txoj hauj lwm ntawm lub grating: DFB qauv feem ntau faib cov qauv ntawm lub sijhawm Bragg grating thoob plaws hauv lub resonator, thiab lub resonator ntawm DBR feem ntau yog tsim los ntawm cov kev xav grating qauv thiab cov cheeb tsam nce kev koom ua ke. qhov kawg nto. Tsis tas li ntawd, DFB lasers siv embedded gratings nrog tsawg refractive index contrast thiab tsawg reflectivity. DBR lasers siv nto gratings nrog siab refractive index contrast thiab siab reflectivity. Ob lub qauv muaj qhov loj dawb spectral ntau yam thiab tuaj yeem ua qhov wavelength tuning yam tsis muaj hom dhia hauv qhov ntau ntawm ob peb nanometers, qhov twg DBR laser muaj ntau qhov kev sib tw ntau dua.DFB laser. Tsis tas li ntawd, sab nraud kab noj hniav kho qhov muag tawm tswv yim thev naus laus zis, uas siv cov khoom siv kho qhov muag sab nraud los tawm tswv yim lub teeb tawm ntawm semiconductor laser nti thiab xaiv qhov zaus, kuj tuaj yeem paub qhov nqaim linewidth ua haujlwm ntawm semiconductor laser.
(2) Fiber lasers
Fiber lasers muaj lub twj tso kua mis hloov dua siab tshiab efficiency, zoo beam zoo thiab siab coupling efficiency, uas yog cov kub kev tshawb fawb cov ntsiab lus nyob rau hauv lub laser teb. Nyob rau hauv cov ntsiab lus ntawm cov ntaub ntawv hnub nyoog, fiber ntau lasers muaj zoo compatibility nrog tam sim no optical fiber kev sib txuas lus systems nyob rau hauv kev ua lag luam. Ib leeg-zaus fiber ntau laser nrog qhov zoo ntawm txoj kab nqaim dav, tsis tshua muaj suab nrov thiab zoo sib xws tau dhau los ua ib qho ntawm cov lus qhia tseem ceeb ntawm nws txoj kev loj hlob.
Tib hom kev ua haujlwm ntev ntev yog lub hauv paus ntawm fiber ntau laser kom ua tiav cov kab dav dav, feem ntau raws li cov qauv ntawm cov resonator ntawm ib zaus fiber ntau laser yuav muab faib ua DFB hom, DBR hom thiab lub nplhaib hom. Ntawm lawv, txoj hauv kev ua haujlwm ntawm DFB thiab DBR ib zaug fiber ntau lasers zoo ib yam li DFB thiab DBR semiconductor lasers.
Raws li pom nyob rau hauv daim duab 1, DFB fiber ntau laser yog sau faib Bragg grating rau hauv fiber. Vim tias qhov ua haujlwm wavelength ntawm oscillator yog cuam tshuam los ntawm lub sij hawm fiber ntau, hom longitudinal tuaj yeem xaiv los ntawm cov lus tawm tswv yim ntawm cov grating. Lub laser resonator ntawm DBR laser feem ntau yog tsim los ntawm ib khub ntawm fiber ntau Bragg gratings, thiab ib hom longitudinal feem ntau yog xaiv los ntawm nqaim band thiab qis reflectivity fiber Bragg gratings. Txawm li cas los xij, vim nws cov resonator ntev, cov qauv nyuaj thiab tsis muaj kev sib ntxub ntxaug ntau zaus, lub nplhaib-zoo li kab noj hniav yog nquag mus rau hom hopping, thiab nws yog ib qho nyuaj rau ua hauj lwm ruaj khov nyob rau hauv tas li longitudinal hom rau lub sij hawm ntev.
Daim duab 1, Ob txoj kab ncaj nraim ntawm ib zausfiber ntau lasers
Post lub sij hawm: Nov-27-2023