Niaj hnub no, peb yuav qhia txog lub laser "monochromatic" rau qhov dav dav - nqaim linewidth laser. Nws qhov tshwm sim ua kom tiav qhov sib txawv hauv ntau daim ntawv thov ntawm laser, thiab nyob rau xyoo tas los no tau siv dav hauv kev tshawb nrhiav nthwv dej gravitational, liDAR, kev faib tawm sensing, kev sib txuas lus optical ceev ceev thiab lwm yam teb, uas yog "lub hom phiaj" uas tsis tuaj yeem ua tiav los ntawm kev txhim kho lub zog laser.
Lub laser kab nqaim yog dab tsi?
Lo lus "kab dav" txhais tau hais tias qhov dav ntawm kab spectral ntawm lub laser hauv qhov zaus, uas feem ntau yog ntsuas raws li qhov dav ib nrab ntawm lub spectrum (FWHM). Qhov dav ntawm kab feem ntau cuam tshuam los ntawm kev tawg ntawm cov atoms lossis ions zoo siab, suab nrov theem, kev co ntawm lub resonator, kub jitter thiab lwm yam sab nraud. Qhov me dua tus nqi ntawm qhov dav ntawm kab, qhov siab dua qhov purity ntawm lub spectrum, uas yog, qhov zoo dua qhov monochromaticity ntawm lub laser. Cov lasers nrog cov yam ntxwv zoo li no feem ntau muaj suab nrov theem lossis zaus me me thiab suab nrov me me. Tib lub sijhawm, qhov me dua tus nqi dav ntawm lub laser, qhov muaj zog dua qhov sib xws, uas yog qhia ua qhov ntev ntev heev.
Kev paub thiab kev siv cov laser kab nqaim
Txwv los ntawm qhov nce kab ntawm cov khoom ua haujlwm ntawm lub laser, nws yuav luag tsis yooj yim sua kom paub qhov tso zis ntawm cov kab nqaim laser los ntawm kev cia siab rau cov oscillator ib txwm muaj. Yuav kom paub txog kev ua haujlwm ntawm cov kab nqaim laser, feem ntau nws yuav tsum siv cov lim dej, grating thiab lwm yam khoom siv los txwv lossis xaiv cov modulus ntev hauv qhov nce spectrum, nce qhov sib txawv ntawm cov kab ntev, yog li muaj ob peb lossis tsuas yog ib qho oscillation ntev hauv lub laser resonator. Hauv cov txheej txheem no, nws feem ntau tsim nyog los tswj cov kev cuam tshuam ntawm suab nrov rau cov zis laser, thiab txo qhov dav ntawm cov kab spectral los ntawm kev co thiab kev hloov pauv kub ntawm qhov chaw sab nraud; Tib lub sijhawm, nws kuj tseem tuaj yeem ua ke nrog kev tshuaj xyuas ntawm theem lossis zaus suab nrov spectral ceev kom nkag siab qhov chaw ntawm suab nrov thiab ua kom zoo dua qhov tsim ntawm lub laser, yog li ua tiav cov zis ruaj khov ntawm cov kab nqaim laser.
Cia peb los saib qhov kev paub txog kev ua haujlwm ntawm ntau hom lasers sib txawv.
(1)Lub tshuab hluav taws xob semiconductor
Cov lasers semiconductor muaj qhov zoo ntawm qhov me me, kev ua haujlwm siab, lub neej ntev thiab cov txiaj ntsig kev lag luam.
Lub Fabry-Perot (FP) optical resonator siv rau hauv cov tsooscov laser semiconductorfeem ntau oscillates nyob rau hauv ntau-longitudinal hom, thiab qhov dav ntawm cov kab tso zis yog qhov dav, yog li nws yog qhov tsim nyog los nce qhov kev tawm tswv yim optical kom tau txais cov zis ntawm cov kab dav nqaim.
Cov lus teb rov qab faib tawm (DFB) thiab Kev cuam tshuam faib tawm Bragg (DBR) yog ob lub lasers sab hauv optical feedback semiconductor. Vim yog lub suab grating me me thiab kev xaiv wavelength zoo, nws yooj yim kom ua tiav qhov ruaj khov ib zaug-zaus nqaim linewidth tso zis. Qhov sib txawv tseem ceeb ntawm ob lub qauv yog qhov chaw ntawm lub grating: lub qauv DFB feem ntau faib cov qauv periodic ntawm Bragg grating thoob plaws hauv lub resonator, thiab lub resonator ntawm DBR feem ntau yog tsim los ntawm cov qauv grating reflection thiab thaj tsam nce ntxiv koom ua ke rau hauv qhov kawg nto. Tsis tas li ntawd, DFB lasers siv embedded gratings nrog qis refractive index sib piv thiab qis reflectivity. DBR lasers siv cov gratings nto nrog siab refractive index sib piv thiab siab reflectivity. Ob lub qauv muaj ntau yam dawb spectral thiab tuaj yeem ua wavelength tuning yam tsis muaj hom dhia hauv ntau yam ntawm ob peb nanometers, qhov twg DBR laser muaj ntau yam tuning dua liDFB laserTsis tas li ntawd xwb, lub tshuab optical feedback sab nraud, uas siv cov khoom siv optical sab nraud los tawm tswv yim rau lub teeb tawm ntawm lub semiconductor laser chip thiab xaiv qhov zaus, kuj tuaj yeem paub txog qhov kev ua haujlwm nqaim ntawm lub semiconductor laser.
(2) Cov laser fiber ntau
Cov laser fiber muaj cov twj tso kua mis hloov pauv siab, zoo beam zoo thiab siab coupling efficiency, uas yog cov ncauj lus tshawb fawb kub hauv thaj chaw laser. Nyob rau hauv lub hnub nyoog xov xwm, fiber lasers muaj kev sib raug zoo nrog cov kab ke sib txuas lus fiber tam sim no hauv kev ua lag luam. Lub laser fiber ib zaug nrog qhov zoo ntawm txoj kab dav, suab nrov qis thiab kev sib raug zoo tau dhau los ua ib qho ntawm cov lus qhia tseem ceeb ntawm nws txoj kev loj hlob.
Ib hom kev ua haujlwm ntev yog lub hauv paus ntawm fiber laser kom ua tiav cov zis kab nqaim, feem ntau raws li cov qauv ntawm lub resonator ntawm ib zaus fiber laser tuaj yeem faib ua DFB hom, DBR hom thiab nplhaib hom. Ntawm lawv, txoj cai ua haujlwm ntawm DFB thiab DBR ib zaus fiber lasers zoo ib yam li DFB thiab DBR semiconductor lasers.
Raws li pom hauv Daim Duab 1, DFB fiber laser yog sau cov Bragg grating faib rau hauv fiber. Vim tias qhov wavelength ua haujlwm ntawm oscillator cuam tshuam los ntawm lub sijhawm fiber, hom longitudinal tuaj yeem xaiv los ntawm kev tawm tswv yim faib tawm ntawm grating. Lub laser resonator ntawm DBR laser feem ntau yog tsim los ntawm ib khub ntawm fiber Bragg gratings, thiab ib hom longitudinal feem ntau yog xaiv los ntawm cov kab nqaim thiab qis reflectivity fiber Bragg gratings. Txawm li cas los xij, vim nws lub resonator ntev, cov qauv nyuaj thiab tsis muaj kev faib tawm zaus zoo, lub nplhaib-puab qhov yog qhov yooj yim rau hom hopping, thiab nws nyuaj rau ua haujlwm ruaj khov hauv hom longitudinal tas mus li rau lub sijhawm ntev.
Daim Duab 1, Ob lub qauv linear ntawm ib zauscov laser fiber ntau
Lub sijhawm tshaj tawm: Kaum Ib Hlis-27-2023