Vim li cas peb yuav tsum paub lub hauv paus ntsiab lus ntawm lasers?
Paub qhov sib txawv ntawm cov semiconductor lasers, fibers, discs, thiabYAG lasertseem tuaj yeem pab kom nkag siab zoo dua thiab koom nrog kev sib tham ntau ntxiv thaum lub sijhawm xaiv.
Cov kab lus feem ntau yog tsom rau cov kev tshawb fawb nrov: cov lus qhia luv luv rau lub hauv paus ntsiab lus ntawm laser tiam, lub ntsiab qauv ntawm lasers, thiab ntau hom lasers.
Ua ntej, lub hauv paus ntsiab lus ntawm laser tiam
Laser yog generated los ntawm kev sib cuam tshuam ntawm lub teeb thiab teeb meem, hu ua stimulated radiation amplification; Kev nkag siab txog kev txhawb nqa hluav taws xob ua kom muaj zog yuav tsum nkag siab Einstein cov ntsiab lus ntawm kev ua kom muaj pa tawm, txhawb nqa kev nqus, thiab txhawb nqa hluav taws xob, nrog rau qee qhov tsim nyog theoretical hauv paus.
Theoretical Basis 1: Bohr Model
Tus qauv Bohr feem ntau muab cov qauv sab hauv ntawm atoms, ua kom yooj yim to taub tias lasers tshwm sim li cas. Lub atom yog tsim los ntawm ib tug nucleus thiab electrons sab nraum lub nucleus, thiab lub orbitals ntawm electrons tsis arbitrary. Cov hluav taws xob tsuas muaj qee qhov orbitals, ntawm cov uas lub hauv nruab nrab lub orbital yog hu ua hauv av xeev; Yog tias ib qho hluav taws xob nyob hauv av, nws lub zog yog qhov qis tshaj. Yog tias ib qho hluav taws xob dhia tawm ntawm lub orbit, nws yog hu ua thawj lub xeev zoo siab, thiab lub zog ntawm thawj lub xeev zoo siab yuav siab dua li ntawm lub xeev hauv av; Lwm lub orbit yog hu ua lub xeev txaus siab thib ob;
Qhov laj thawj vim li cas laser tuaj yeem tshwm sim yog vim tias cov hluav taws xob yuav txav mus rau hauv qhov sib txawv hauv cov qauv no. Yog tias cov hluav taws xob nqus hluav taws xob, lawv tuaj yeem khiav ntawm lub xeev hauv av mus rau lub xeev zoo siab; Yog tias ib qho hluav taws xob rov qab los ntawm lub xeev zoo siab mus rau hauv av, nws yuav tso tawm lub zog, uas feem ntau tso tawm hauv daim ntawv laser.
Theoretical Basis 2: Einstein's Stimulated Radiation Theory
Xyoo 1917, Einstein tau tshaj tawm txoj kev xav ntawm lub zog hluav taws xob, uas yog lub hauv paus theoretical rau lasers thiab laser ntau lawm: kev nqus los yog emission ntawm cov teeb meem yog qhov tseem ceeb ntawm kev cuam tshuam ntawm cov hluav taws xob hluav taws xob thiab cov khoom uas tsim teeb meem, thiab nws cov tub ntxhais kawm. essence yog qhov kev hloov ntawm cov khoom ntawm cov qib sib txawv zog. Muaj peb yam txheej txheem sib txawv hauv kev sib cuam tshuam ntawm lub teeb thiab teeb meem: spontaneous emission, stimulated emission, thiab stimulated absorption. Rau ib lub kaw lus uas muaj coob tus hais, cov txheej txheem peb ib txwm nyob ua ke thiab muaj kev sib raug zoo.
Spontaneous emission:
Raws li pom nyob rau hauv daim duab: ib tug electron nyob rau hauv high-zog E2 spontaneously hloov mus rau lub low-zog theem E1 thiab emits ib tug photon nrog ib tug zog ntawm hv, thiab hv = E2-E1; Cov txheej txheem kev hloov pauv tsis raug thiab tsis cuam tshuam no yog hu ua spontaneous transition, thiab lub teeb nthwv dej tawm los ntawm kev hloov pauv hloov pauv hu ua spontaneous radiation.
Cov yam ntxwv ntawm spontaneous emission: Txhua photon yog ywj siab, nrog txawv cov lus qhia thiab theem, thiab lub sij hawm tshwm sim kuj yog random. Nws belongs rau incoherent thiab chaotic teeb, uas tsis yog lub teeb yuav tsum tau los ntawm lub laser. Yog li ntawd, lub laser tiam txheej txheem yuav tsum tau txo cov hom teeb stray. Qhov no kuj yog ib qho ntawm cov laj thawj vim li cas lub wavelength ntawm ntau yam lasers muaj teeb pom kev zoo. Yog tias tswj tau zoo, qhov kev faib ua feem ntawm emissions nyob rau hauv lub laser tuaj yeem tsis quav ntsej. Lub purer lub laser, xws li 1060 nm, nws yog tag nrho 1060 nm, hom laser no muaj ib tug kuj ruaj khov tus nqi thiab lub zog.
Stimulated absorption:
Electrons nyob rau theem qis zog (tsawg orbitals), tom qab absorbing photons, hloov mus rau ntau zog zog (high orbitals), thiab cov txheej txheem no hu ua stimulated absorption. Stimulated absorption yog qhov tseem ceeb thiab yog ib qho ntawm cov txheej txheem tseem ceeb ntawm kev nqus dej. Lub twj tso kua mis ntawm lub laser muab lub zog photon los ua cov khoom hauv qhov nce nruab nrab mus rau kev hloov pauv thiab tos rau cov hluav taws xob txhawb zog ntawm qib siab zog, emitting lub laser.
Stimulated hluav taws xob:
Thaum irradiated los ntawm lub teeb ntawm lub zog sab nraud (hv = E2-E1), cov hluav taws xob ntawm lub zog siab yog zoo siab los ntawm cov photon sab nraud thiab dhia mus rau theem qis zog (qhov siab khiav mus rau qhov qis orbit). Nyob rau tib lub sij hawm, nws emits ib tug photon uas yog raws nraim tib yam li sab nraud photon. Cov txheej txheem no tsis nqus cov thawj excitation lub teeb, yog li ntawd yuav muaj ob zoo tib yam photons, uas yuav to taub raws li lub electron spits tawm lub yav tas los absorbed photon, Cov txheej txheem luminescence no hu ua stimulated hluav taws xob, uas yog cov txheej txheem rov qab ntawm stimulated absorption.
Tom qab qhov kev xav tau meej, nws yooj yim heev los tsim lub laser, raws li qhia hauv daim duab saum toj no: nyob rau hauv ib txwm muaj kev ruaj ntseg ntawm cov khoom siv, feem ntau ntawm cov hluav taws xob nyob hauv av, electrons hauv av, thiab laser nyob ntawm. stimulated hluav taws xob. Yog li ntawd, cov qauv ntawm lub laser yog tso cai rau stimulated absorption ua ntej, nqa electrons mus rau lub siab zog, thiab ces muab ib tug excitation ua rau ib tug loj tus naj npawb ntawm high zog theem electrons mus undergo stimulated hluav taws xob, tso photons, los ntawm qhov no, laser tuaj yeem tsim tau. Tom ntej no, peb yuav qhia txog cov qauv laser.
Laser qauv:
Sib piv cov qauv laser nrog cov txheej txheem laser tiam tau hais ua ntej ib los ntawm ib qho:
Cov xwm txheej ntawm qhov tshwm sim thiab cov qauv sib xws:
1. Muaj qhov nce nruab nrab uas muab cov nyhuv amplification raws li lub laser ua haujlwm nruab nrab, thiab nws cov khoom ua kom muaj zog muaj cov qauv siv hluav taws xob tsim nyog rau kev tsim hluav taws xob tsim hluav taws xob (feem ntau tuaj yeem tso cov hluav taws xob mus rau lub zog orbitals thiab muaj nyob rau qee lub sijhawm. , thiab tom qab ntawd tso tawm photons hauv ib qho pa los ntawm kev txhawb zog hluav taws xob);
2. Muaj ib qho excitation qhov chaw (tswj qhov chaw) uas tuaj yeem tso cov hluav taws xob los ntawm theem qis mus rau theem siab, ua rau cov khoom sib txawv ntawm cov qib siab thiab qis ntawm lub laser (piv txwv li, thaum muaj cov khoom siv hluav taws xob ntau dua. Cov khoom siv hluav taws xob tsawg), xws li lub teeb xenon hauv YAG lasers;
3. Muaj cov kab noj hniav resonant uas tuaj yeem ua tiav laser oscillation, ua kom ntev ua haujlwm ntawm cov khoom siv laser ua haujlwm, tshuaj ntsuam lub teeb yoj hom, tswj kev nthuav tawm ntawm cov nqaj, xaiv kom nthuav dav cov hluav taws xob ntau zaus los txhim kho monochromaticity (kom ntseeg tau tias cov laser yog outputted ntawm ib tug tej yam zog).
Cov qauv sib raug tau pom hauv daim duab saum toj no, uas yog ib qho yooj yim qauv ntawm YAG laser. Lwm cov qauv yuav nyuaj dua, tab sis lub hauv paus yog qhov no. Lub laser tiam txheej txheem yog qhia nyob rau hauv daim duab:
Laser kev faib tawm: feem ntau cais los ntawm kev nce nruab nrab lossis los ntawm daim ntawv laser zog
Tau txais kev faib nruab nrab:
Cov pa roj carbon dioxide laser: Qhov nce nruab nrab ntawm carbon dioxide laser yog helium thiabCO2 laser,nrog lub laser wavelength ntawm 10.6um, uas yog ib qho ntawm cov khoom lag luam laser ntxov tshaj plaws tau tsim tawm. Lub laser vuam thaum ntxov yog feem ntau raws li carbon dioxide laser, uas yog tam sim no tsuas yog siv rau vuam thiab txiav cov ntaub ntawv uas tsis yog-hlau (fab, plastics, ntoo, thiab lwm yam). Tsis tas li ntawd, nws kuj yog siv rau ntawm lithography tshuab. Cov pa roj carbon dioxide laser tsis tuaj yeem kis tau los ntawm fiber ntau optical thiab taug kev los ntawm spatial optical paths, Tongkuai thaum ntxov tau ua tiav zoo, thiab siv cov cuab yeej txiav ntau;
YAG (yttrium aluminium garnet) laser: YAG crystals doped nrog neodymium (Nd) lossis yttrium (Yb) hlau ions yog siv los ua lub laser nce nruab nrab, nrog emission wavelength ntawm 1.06um. Lub YAG laser tuaj yeem tso tawm ntau dua pulses, tab sis qhov nruab nrab lub zog qis, thiab lub zog siab tuaj yeem ncav cuag 15 npaug ntawm lub zog nruab nrab. Yog hais tias nws yog ib tug mas mem tes laser, nruam tso zis tsis tau tiav; Tab sis nws tuaj yeem kis tau los ntawm cov khoom siv kho qhov muag, thiab tib lub sijhawm, qhov nqus ntawm cov ntaub ntawv hlau nce ntxiv, thiab nws tau pib siv rau hauv cov ntaub ntawv muaj kev cuam tshuam siab, thawj zaug hauv 3C teb;
Fiber laser: Tam sim no lub ntsiab hauv kev lag luam siv ytterbium doped fiber ntau li qhov nruab nrab nce, nrog lub wavelength ntawm 1060nm. Nws tau muab faib ua fiber ntau thiab disc lasers raws li cov duab ntawm qhov nruab nrab; Fiber optic sawv cev rau IPG, thaum disc sawv cev Tongkuai.
Semiconductor laser: Qhov nruab nrab nce yog semiconductor PN kev sib tshuam, thiab lub wavelength ntawm semiconductor laser feem ntau yog 976nm. Tam sim no, semiconductor ze-infrared lasers feem ntau yog siv rau cladding, nrog lub teeb me ntsis saum 600um. Laserline yog ib lub lag luam sawv cev ntawm semiconductor lasers.
Muab faib los ntawm daim ntawv ntawm lub zog ua haujlwm: Pulse laser (PULSE), quasi nruam laser (QCW), nruam laser (CW)
Pulse laser: nanosecond, picosecond, femtosecond, no high-frequency mem tes laser (ns, mem tes dav) feem ntau ua tau siab ncov lub zog, siab zaus (MHZ) ua, siv rau kev ua nyias tooj liab thiab txhuas cov ntaub ntawv sib txawv, nrog rau kev tu feem ntau. . Los ntawm kev siv lub siab ncov siab, nws tuaj yeem yaj cov khoom siv hauv paus sai sai, nrog lub sijhawm ua haujlwm tsawg thiab cov cua sov me me. Nws muaj qhov zoo hauv kev ua cov ntaub ntawv ultra-nyias (hauv qab 0.5mm);
Quasi nruam laser (QCW): Vim muaj qhov rov ua haujlwm siab thiab lub voj voog qis (qis dua 50%), cov mem tes dav ntawmQCW laserncav cuag 50 us-50 ms, sau qhov sib txawv ntawm kilowatt qib nruam fiber ntau laser thiab Q-hloov pulse laser; Lub zog siab tshaj plaws ntawm quasi nruam fiber ntau laser tuaj yeem ncav cuag 10 npaug ntawm lub zog nruab nrab hauv kev ua haujlwm txuas ntxiv. QCW lasers feem ntau muaj ob hom, ib qho txuas txuas ntxiv ntawm lub zog qis, thiab lwm yam yog lub zog laser welding nrog lub zog siab tshaj plaws ntawm 10 npaug ntawm lub zog nruab nrab, uas tuaj yeem ua tiav cov ntaub ntawv tuab thiab ntau dua cov cua sov, thaum tseem tswj cov cua sov hauv ib tsawg heev;
Nruam Laser (CW): Qhov no yog feem ntau siv, thiab feem ntau ntawm cov lasers pom nyob rau hauv lub lag luam yog CW lasers uas tsis tu ncua tso zis laser rau vuam ua. Fiber lasers tau muab faib ua ib hom thiab ntau hom lasers raws li qhov sib txawv ntawm cov tub ntxhais diameters thiab beam zoo, thiab tuaj yeem hloov mus rau qhov sib txawv daim ntawv thov scenarios.
Post lub sij hawm: Dec-20-2023
