Cov plaub thev naus laus zis no tau sib tham ua ke vim tias lawv txhua tus cuam tshuam ncaj qha rau cov khoom tso tawm ntawm lub laser resonant kab noj hniav.
1. Hom xaiv:
Kev xaiv hom yog qhov kev xaiv zaus. Feem ntau cov lasers siv ntev resonant kab noj hniav kom tau txais lub zog tso zis ntau dua, uas ua rau laser tso zis ntau hom. Txawm li cas los xij, piv nrog cov qauv kev txiav txim siab dua, cov hom kev hloov pauv tseem ceeb (TEM00 hom) muaj cov yam ntxwv ntawm qhov ci ntsa iab, me me divergence lub kaum sab xis, tsis sib xws radial lub teeb siv sib faib, thiab ib zaug oscillation zaus. Nws muaj qhov zoo tshaj plaws spatial thiab lub cev cuam tshuam. Yog li ntawd, ib qho tseem ceeb transverse hom laser yog qhov zoo tshaj plaws coherent lub teeb, uas yog ib qho tseem ceeb heev rau kev siv xws li laser interferometry, spectral tsom xam, thiab laser ua. Txhawm rau ua kom tau raws li cov xwm txheej no, kev ntsuas los txwv laser oscillation yuav tsum tau txais kev pom zoo los txwv kev ua haujlwm ntawm feem ntau resonant zaus hauv ntau hom lasers, thiab siv hom kev xaiv tshuab kom tau txais ib hom ib zaug ib zaug laser tso zis.
Kev xaiv hom yog muab faib ua ob txoj hauv kev: ib qho yog xaiv laser longitudinal hom; lwm qhov yog xaiv laser transverse hom. Tus qub muaj kev cuam tshuam ntau dua ntawm cov zis zaus ntawm lub laser thiab tuaj yeem txhim kho kev sib raug zoo ntawm laser; tom kawg feem ntau cuam tshuam rau qhov sib xws ntawm lub teeb siv ntawm lub laser tso zis thiab txhim kho qhov ci ntawm lub laser.
1)Longitudinal hom xaiv: Txhawm rau txhim kho lub monochromaticity thiab coherence ntev ntawm lub teeb, lub laser yuav tsum tau ua haujlwm nyob rau hauv ib hom longitudinal. Txawm li cas los xij, ntau lub lasers feem ntau muaj ntau hom longitudinal oscillating tib lub sijhawm. Yog li ntawd, txhawm rau tsim ib hom ntev ntev laser, yuav tsum siv txoj kev xaiv zaus. Cov txheej txheem feem ntau muaj xws li: txoj kev luv kab noj hniav, Fabry-Ploy etalon txoj kev, peb daim iav, thiab lwm yam.
2)Transverse hom xaiv: Cov xwm txheej rau laser oscillation yog qhov nce coefficient yuav tsum ntau dua qhov poob coefficient. Cov kev poob tuaj yeem muab faib ua kab emission poob cuam tshuam nrog kev txiav txim siab hloov pauv thiab lwm yam kev poob qis ntawm hom oscillation. Lub ntsiab lus ntawm kev xaiv hom kev hloov pauv tseem ceeb yog ua kom TEM 00 hom mus txog oscillation tej yam kev mob thiab suppress lub oscillation ntawm siab dua-order transverse hom. Yog li ntawd, peb tsuas yog yuav tsum tau tswj cov kab emission poob ntawm txhua hom kev txiav txim siab kom ua tiav lub hom phiaj ntawm kev xaiv transverse hom. Feem ntau hais lus, tsuav yog TEM01 hom thiab TEM10 hom oscillations uas yog ib qho kev txiav txim siab dua li qhov tseem ceeb hloov pauv tuaj yeem raug txwv, oscillations ntawm lwm hom kev txiav txim siab dua tuaj yeem raug txwv. Cov txheej txheem muaj xws li: aperture method, tsom aperture method thiab intra-cavity telescope method, concave-convex kab noj hniav, siv Q-hloov hom xaiv, thiab lwm yam.
2. Zaus stabilization:
Tom qab lub laser tau txais ib zaus oscillation los ntawm kev xaiv hom, lub resonant zaus tseem yuav txav mus rau hauv tag nrho cov kab dav vim qhov kev hloov hauv sab hauv thiab sab nraud. Qhov tshwm sim no hu ua "frequency drift." Vim lub hav zoov ntawm drift, qhov teeb meem ntawm laser zaus stability tshwm sim. Lub hom phiaj ntawm kev ruaj ntseg zaus yog los sim tswj cov kev tswj tau qhov no kom txo tau lawv qhov cuam tshuam nrog cov zaus oscillation, yog li txhim kho qhov ruaj khov ntawm laser zaus.
Frequency stability muaj ob yam: zaus stability thiab zaus reproducibility. Frequency stability yog hais txog qhov sib piv ntawm cov zaus drift ntawm lub laser mus rau lub oscillation zaus nyob rau hauv ib tug tas mus li ua hauj lwm lub sij hawm. Qhov sib piv me me, qhov ntau zaus stability. Kev tsim tawm ntau zaus yog qhov sib txawv ntawm cov zaus thaum lub laser siv nyob rau hauv ntau qhov chaw. Txoj kev stabilization zaus muab faib ua ob hom: passive thiab nquag. Cov txheej txheem tshwj xeeb zaus stabilization muaj xws li: Lamb sag method thiab saturation absorption method.
3. Q-hloov:
Feem ntau, lub teeb pulses tso zis los ntawm solid-state mem tes lasers tsis yog ib tug du pulses, tab sis ib tug sib lawv liag ntawm me me ncov pulses nrog sib txawv siv thiab dav nyob rau hauv microsecond ntau. Lub teeb mem tes no nyob rau ntau pua microseconds lossis milliseconds, thiab nws lub zog siab tshaj plaws tsuas yog kaum ntawm kilowatts, uas yog deb ntawm kev ua tau raws li cov kev xav tau ntawm kev siv tswv yim xws li laser radar thiab laser ntau yam. Vim li no, qee tus neeg tau thov lub tswv yim ntawm Q-hloov, uas tau txhim kho cov txiaj ntsig ntawm laser pulses los ntawm ntau qhov kev txiav txim ntawm qhov loj, compressed lub mem tes dav mus rau qib nanosecond, thiab lub ncov lub zog yog siab li gigawatts.
Q yog hais txog qhov zoo tshaj plaws ntawm lub laser resonant kab noj hniav. Cov mis mos tshwj xeeb yog Q=2T"Zoo khaws cia rau hauv cov kab noj hniav resonant/Energy poob ib lub voj voog oscillation.
Lub sijhawm no, lub hauv paus ntsiab lus ntawm laser oscillation Q-hloov: ib txoj hauv kev yog siv los ua kom lub resonant kab noj hniav nyob rau hauv ib tug high-tsis thiab qis-Q nqi xeev thaum pib ntawm kev siv. Qhov pib ntawm oscillation yog siab heev, thiab txawm hais tias cov particle ntom ntom inversion tooj accumulates mus rau qib siab heev, nws yuav tsis tsim oscillation; Thaum tus lej inversion nce mus txog qhov kawg ntawm tus nqi, Q tus nqi ntawm cov kab noj hniav yog dheev nce, uas yuav ua rau qhov nce ntawm lub laser nruab nrab kom dhau qhov pib, thiab oscillation yuav tshwm sim sai heev. Lub sijhawm no, lub zog ntawm cov khoom khaws cia hauv lub xeev metastable yuav raug hloov mus rau hauv lub zog ntawm photons, thiab cov photons yuav nce siab heev. Lub laser tuaj yeem tso tawm lub laser mem tes nrog lub siab ncov lub zog thiab nqaim dav.
Vim tias qhov poob ntawm qhov resonant kab noj hniav muaj xws li kev xav tsis zoo, kev nqus tsis zoo, tawg tawg, tawg tawg thiab kev sib kis tsis zoo, ntau txoj kev siv los tswj ntau hom kev poob los tsim cov Q-switching technologies sib txawv. Tam sim no, ntau Q-switching technologies yog: acousto-optic Q-switching, electro-optic Q-switching thiab zas Q-hloov.
4. Hom xauv:
Q-switching tuaj yeem nthuav dav lub laser pulse dav thiab tau txais laser pulses nrog lub mem tes dav ntawm qhov kev txiav txim ntawm microseconds thiab lub zog siab tshaj plaws ntawm qhov kev txiav txim ntawm gigawatts. Hom locking tshuab yog ib lub tshuab uas ntxiv modulates lub laser nyob rau hauv ib txoj kev tshwj xeeb, yuam cov theem ntawm ntau yam longitudinal hom oscillating nyob rau hauv lub laser yuav tsum tau kho, kom txhua hom yuav coherently superimposed kom tau ultrashort pulses. Siv hom xauv tshuab, ultrashort laser pulses nrog lub mem tes dav ntawm qhov kev txiav txim ntawm femtoseconds thiab lub zog siab tshaj qhov kev txiav txim ntawm T watts tuaj yeem tau txais. Hom xauv tshuab ua rau lub zog laser muaj zog heev hauv lub sijhawm thiab tam sim no yog cov thev naus laus zis tshaj plaws kom tau txais lub zog siab tshaj plaws lasers.
Hom kev xauv lub hauv paus ntsiab lus: Feem ntau, cov lasers uas tsis yog-uniformly broadened ib txwm tsim ntau hom longitudinal. Txij li thaum tsis muaj kev sib raug zoo ntawm qhov zaus thiab thawj theem ntawm txhua hom, txhua hom yog incoherent nrog ib leeg, yog li lub teeb siv tawm los ntawm ntau hom longitudinal yog incoherent ntxiv ntawm txhua hom longitudinal. Lub teeb pom kev siv hluav taws xob hloov pauv tsis tu ncua raws sijhawm. Hom kev kaw cia tso cai rau ntau hom longitudinal uas yuav muaj nyob rau hauv lub resonant kab noj hniav kom oscillate synchronously, ua kom lub zaus ntawm txhua oscillation hom sib npaug thiab ua rau lawv thawj theem tsis tu ncua, thiaj li hais tias lub laser outputs ib tug luv luv mem tes sib lawv liag nrog tsis tu ncua thiab sib npaug ntawm lub sij hawm.
Hom locking tshuab yog muab faib ua active hom locking thiab passive hom locking. Active hom locking: ntxig lub modulator nrog ib tug modulation zaus v=c/2L rau hauv resonant kab noj hniav los modulate lub amplitude thiab theem ntawm lub laser tso zis kom ua tau synchronous vibration ntawm txhua longitudinal hom. Passive hom locking: ntxig lub thawv xim nrog cov yam ntxwv nqus dej rau hauv lub laser kab noj hniav. Qhov nqus coefficient ntawm lub thawv dye nrog cov yam ntxwv zoo nqus dej yuav txo qis nrog qhov nce ntawm lub teeb siv. Nyob rau hauv lub laser, raws li lub optical twj tso kua mis excites cov khoom ua hauj lwm, txhua longitudinal hom yuav tshwm sim randomly, thiab lub teeb teb yuav fluctuate nyob rau hauv kev siv vim lawv superposition. Thaum qee cov qauv longitudinal sib koom ua ke los ntawm lub caij nyoog, qhov chaw uas muaj lub teeb pom kev zoo tshwm sim, thaum lwm qhov tsis muaj zog. Cov khoom muaj zog no yog absorbed tsawg dua los ntawm cov xim thiab qhov poob tsis loj. Qhov tsis muaj zog yog absorbed ntau los ntawm cov xim thiab ua tsis muaj zog. Raws li qhov tshwm sim ntawm lub teeb pom kev dhau los ntawm cov xim ntau zaus, qhov muaj zog thiab tsis muaj zog yog qhov txawv txav, thiab thaum kawg cov longitudinal hom coherent txhim kho qhov chaw raug xaiv nyob rau hauv daim ntawv ntawm nqaim pulses. Passive hom locking muaj qee qhov kev xav tau ntawm cov khoom siv kho qhov muag ntawm lub thawv xim: cov kab nqus ntawm cov xim yuav tsum nyob ze rau ntawm lub laser wavelength; txoj kab dav ntawm txoj kab nqus yuav tsum ntau dua lossis sib npaug ntawm cov kab laser dav; thiab lub sij hawm so yuav tsum luv dua lub sij hawm nws yuav siv sij hawm rau lub plawv dhia rov qab mus rau hauv kab noj hniav.
