Ka'idar Samar da Laser

Me yasa muke buƙatar sanin ƙa'idar lasers?

Sanin bambance-bambance tsakanin lasers na semiconductor na gama gari, zaruruwa, faifan diski, daLaser na YAGzai iya taimakawa wajen samun fahimta mai kyau da kuma shiga cikin ƙarin tattaunawa yayin tsarin zaɓe.

Labarin ya fi mayar da hankali kan kimiyyar da ta shahara: taƙaitaccen gabatarwa game da ƙa'idar samar da laser, babban tsarin laser, da kuma nau'ikan laser da yawa da aka saba da su.

Da farko, ƙa'idar samar da laser

Ana samar da laser ta hanyar hulɗar da ke tsakanin haske da abu, wanda aka sani da ƙara yawan hasken da aka ƙarfafa; Fahimtar ƙara yawan hasken da aka ƙarfafa yana buƙatar fahimtar ra'ayoyin Einstein game da fitar da iska ba zato ba tsammani, sha, da kuma ƙara yawan hasken da aka ƙarfafa, da kuma wasu muhimman tushe na ka'idoji.

Tushen Ka'ida na 1: Tsarin Bohr

Tsarin Bohr galibi yana samar da tsarin ciki na atoms, wanda hakan ke sauƙaƙa fahimtar yadda lasers ke faruwa. Atom ya ƙunshi nucleus da electrons a wajen nucleus, kuma orbital na electrons ba na son rai ba ne. Electrons suna da wasu orbital kawai, daga cikinsu ana kiran mafi orbital na ciki yanayin ƙasa; Idan electron yana cikin yanayin ƙasa, makamashinsa shine mafi ƙasƙanci. Idan electron ya yi tsalle daga zagaye, ana kiransa yanayin farin ciki na farko, kuma kuzarin yanayin farin ciki na farko zai fi na yanayin ƙasa; wani zagaye ana kiransa yanayin farin ciki na biyu;

Dalilin da yasa laser zai iya faruwa shine saboda electrons zasu motsa a cikin yanayi daban-daban a cikin wannan samfurin. Idan electrons suna shan makamashi, zasu iya gudu daga yanayin ƙasa zuwa yanayin farin ciki; Idan electron ya dawo daga yanayin farin ciki zuwa yanayin ƙasa, zai saki makamashi, wanda galibi ana fitar dashi a cikin nau'in laser.

Tushen Ka'ida na 2: Ka'idar Hasken da Einstein ya Ƙarfafa

A shekarar 1917, Einstein ya gabatar da ka'idar radiation mai motsawa, wanda shine tushen ka'idar samar da laser da laser: sha ko fitar da abu a zahiri sakamakon hulɗar da ke tsakanin filin radiation da barbashi da suka samar da abu, kuma ainihin asalinsa shine sauyawar barbashi tsakanin matakan kuzari daban-daban. Akwai matakai uku daban-daban a cikin hulɗar da ke tsakanin haske da abu: fitar da abu ba zato ba tsammani, fitar da abu mai motsawa, da kuma sha. Ga tsarin da ke ɗauke da adadi mai yawa na barbashi, waɗannan matakai uku koyaushe suna rayuwa tare kuma suna da alaƙa sosai.

Fitar da iskar gas ba tare da wata-wata ba:

Kamar yadda aka nuna a cikin hoton: wani electron a matakin makamashi mai girma E2 yana canzawa zuwa matakin makamashi mai ƙarancin ƙarfi E1 kuma yana fitar da photon mai ƙarfin hv, da hv=E2-E1; Wannan tsari na sauyawa na bazata kuma mara alaƙa ana kiransa sauyin bazata, kuma raƙuman haske da sauye-sauyen bazata ke fitarwa ana kiransu radiation na bazata.

Halayen fitar da haske kwatsam: Kowane photon yana da zaman kansa, tare da alkibla da matakai daban-daban, kuma lokacin faruwa shima bazuwar ne. Yana cikin hasken da ba shi da tsari da rudani, wanda ba shine hasken da laser ke buƙata ba. Saboda haka, tsarin samar da laser yana buƙatar rage wannan nau'in hasken da ya ɓace. Wannan kuma yana ɗaya daga cikin dalilan da yasa tsawon hasken laser daban-daban ke da hasken da ya ɓace. Idan aka sarrafa shi da kyau, za a iya yin watsi da rabon fitar da haske kwatsam a cikin laser. Mafi tsarkin laser, kamar 1060 nm, duka 1060 nm ne. Wannan nau'in laser yana da ƙimar sha da ƙarfi mai ƙarfi.

Shawarwarin da aka ƙarfafa:

Electrons a ƙananan matakan kuzari (ƙananan orbitals), bayan shan photons, canzawa zuwa manyan matakan kuzari (masu orbital masu yawa), kuma wannan tsari ana kiransa da stimulated absorption. stimulated absorption yana da mahimmanci kuma yana ɗaya daga cikin mahimman hanyoyin famfo. Tushen famfo na laser yana ba da makamashin photon don sa barbashi a cikin matsakaicin riba su canza kuma su jira radiation mai ƙarfafawa a manyan matakan kuzari, suna fitar da laser.

Radiation mai ƙarfafawa:

Idan hasken makamashin waje ya haskaka shi (hv=E2-E1), electron a matakin makamashi mai girma yana motsawa ta hanyar photon na waje kuma yana tsalle zuwa matakin makamashi mai ƙarancin ƙarfi (babban kewaya yana gudana zuwa ƙaramin kewaya). A lokaci guda, yana fitar da photon wanda yayi daidai da photon na waje. Wannan tsari baya sha asalin hasken motsawa, don haka za a sami photon guda biyu iri ɗaya, waɗanda za a iya fahimta yayin da electron ke fitar da photon da aka sha a baya. Wannan tsari na haske ana kiransa radiation mai ƙarfafawa, wanda shine tsarin juyawa na sha mai ƙarfafawa.

Bayan ka'idar ta bayyana sarai, yana da sauƙi a gina laser, kamar yadda aka nuna a cikin hoton da ke sama: a ƙarƙashin yanayin daidaiton abu na yau da kullun, yawancin electrons suna cikin yanayin ƙasa, electrons suna cikin yanayin ƙasa, kuma laser ya dogara da radiation mai ƙarfafawa. Saboda haka, tsarin laser shine don ba da damar sha mai ƙarfafawa ya fara faruwa, yana kawo electrons zuwa matakin makamashi mai girma, sannan kuma yana samar da abin motsa jiki don sa adadi mai yawa na electrons masu matakin makamashi su fuskanci radiation mai ƙarfafawa, suna fitar da photons. Daga wannan, ana iya samar da laser. Na gaba, za mu gabatar da tsarin laser.

Tsarin Laser:

Haɗa tsarin laser ɗin da yanayin samar da laser da aka ambata a baya ɗaya bayan ɗaya:

Yanayin faruwar da kuma tsarin da ya dace:

1. Akwai wani abu mai amfani wanda ke samar da tasirin ƙara girma kamar yadda na'urar laser ke aiki, kuma barbashi masu aiki suna da tsarin matakin kuzari wanda ya dace da samar da hasken da aka ƙarfafa (galibi yana iya tura electrons zuwa ga orbital masu ƙarfi kuma yana wanzuwa na wani lokaci, sannan ya saki photons a cikin numfashi ɗaya ta hanyar hasken da aka ƙarfafa);

2. Akwai tushen motsawa na waje (tushen famfo) wanda zai iya fitar da electrons daga ƙasa zuwa sama, yana haifar da juyawar adadin barbashi tsakanin matakan sama da ƙasa na laser (watau, lokacin da akwai barbashi masu ƙarfi fiye da barbashi masu ƙarancin kuzari), kamar fitilar xenon a cikin lasers na YAG;

3. Akwai rami mai ƙarfi wanda zai iya cimma juyawar laser, ƙara tsawon aiki na kayan aikin laser, duba yanayin raƙuman haske, sarrafa alkiblar yaɗuwar hasken, zaɓi ƙara yawan hasken da aka ƙarfafa don inganta monochromaticity (tabbatar da cewa an fitar da laser ɗin a wani takamaiman kuzari).

An nuna tsarin da ya dace a cikin hoton da ke sama, wanda shine tsari mai sauƙi na laser YAG. Sauran tsare-tsare na iya zama mafi rikitarwa, amma ainihin shine wannan. Tsarin samar da laser an nuna shi a cikin hoton:

Rarraba Laser: gabaɗaya ana rarraba su ta hanyar gain medium ko ta hanyar laser energy form

Sami matsakaicin rarrabuwa:

Laser ɗin carbon dioxide: Ma'aunin samun sinadarin laser na carbon dioxide shine helium daLaser CO2,tare da tsawon laser na 10.6um, wanda shine ɗaya daga cikin samfuran laser na farko da aka ƙaddamar. Walda na laser na farko ya dogara ne akan laser carbon dioxide, wanda a halin yanzu ana amfani da shi musamman don walda da yanke kayan da ba na ƙarfe ba (yadi, robobi, itace, da sauransu). Bugu da ƙari, ana amfani da shi kuma akan injunan lithography. Ba za a iya yada laser carbon dioxide ta hanyar zare na gani ba kuma yana tafiya ta hanyoyin gani na sarari. An yi Tongkuai na farko da kyau, kuma an yi amfani da kayan aikin yankewa da yawa;

Laser na YAG (yttrium aluminum garnet): Ana amfani da lu'ulu'u na YAG waɗanda aka yi musu allurar ƙarfe na neodymium (Nd) ko yttrium (Yb) a matsayin matsakaicin ƙarfin laser, tare da tsawon fitar da hayaki na 1.06um. Laser na YAG zai iya fitar da bugun jini mafi girma, amma matsakaicin ƙarfin yana da ƙasa, kuma ƙarfin kololuwa zai iya kaiwa sau 15 na matsakaicin ƙarfin lantarki. Idan galibi laser ne na bugun jini, ba za a iya cimma ci gaba da fitarwa ba; Amma ana iya watsa shi ta hanyar zare na gani, kuma a lokaci guda, ƙimar sha na kayan ƙarfe yana ƙaruwa, kuma ana fara amfani da shi a cikin kayan haske masu yawa, waɗanda aka fara amfani da su a filin 3C;

Laser ɗin fiber: Babban abin da ake amfani da shi a kasuwa a yanzu yana amfani da zare mai kauri ytterbium a matsayin matsakaicin riba, tare da tsawon tsayin 1060nm. An ƙara raba shi zuwa zare da laser ɗin diski bisa ga siffar matsakaiciyar; Fiber optic yana wakiltar IPG, yayin da diski yana wakiltar Tongkuai.

Laser na Semiconductor: Matsakaicin gain shine mahadar PN ta semiconductor, kuma tsawon laser na semiconductor galibi yana kan 976nm. A halin yanzu, ana amfani da laser na semiconductor kusa da infrared galibi don rufewa, tare da tabo masu haske sama da 600um. Laserline wakili ne na laser na semiconductor.

An rarraba su ta hanyar aikin makamashi: Laser Pulse (PULSE), Laser mai ci gaba da kusan (QCW), Laser mai ci gaba da kusan (CW)

Laser na Pulse: nanosecond, picosecond, femtosecond, wannan laser mai yawan mitar bugun jini (ns, pulse width) sau da yawa yana iya cimma babban kuzari, sarrafa mitar mai yawa (MHZ), wanda ake amfani da shi don sarrafa kayan jan ƙarfe da aluminum marasa kama da juna, da kuma tsaftacewa galibi. Ta hanyar amfani da makamashi mai yawa, yana iya narke kayan tushe cikin sauri, tare da ƙarancin lokacin aiki da ƙaramin yanki da zafi ke shafar. Yana da fa'idodi wajen sarrafa kayan da ba su da sirara (ƙasa da 0.5mm);

Laser mai ci gaba da aiki (QCW): Saboda yawan maimaitawa da kuma ƙarancin zagayowar aiki (ƙasa da 50%), faɗin bugun jini naLaser QCWyana kaiwa 50 us-50 ms, yana cike gibin da ke tsakanin laser fiber mai ci gaba da matakin kilowatt da laser mai canzawa na Q; Ƙarfin kololuwar laser mai ci gaba da kusan ci gaba zai iya kaiwa sau 10 matsakaicin ƙarfi a ƙarƙashin aikin yanayin ci gaba. Lasers na QCW gabaɗaya suna da yanayi biyu, ɗaya shine walda mai ci gaba da ƙarancin ƙarfi, ɗayan kuma walda mai pulsed laser mai ƙarfin kololuwa sau 10 matsakaicin ƙarfi, wanda zai iya cimma kayan da suka fi kauri da ƙarin walda mai zafi, yayin da kuma yake sarrafa zafi a cikin ƙaramin kewayon;

Laser Mai Ci Gaba (CW): Wannan shine mafi yawan amfani, kuma yawancin lasers da ake gani a kasuwa sune lasers CW waɗanda ke ci gaba da fitar da laser don sarrafa walda. Ana raba lasers ɗin fiber zuwa lasers na yanayi ɗaya da na yanayi da yawa bisa ga diamita daban-daban na tsakiya da halayen katako, kuma ana iya daidaita su zuwa yanayi daban-daban na aikace-aikace.