Luong Thi Ha

8/6/2019 Luong Thi Ha

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BGIO DC VO TOTRNG I HC S PHM H NI

TIU LUNLAZER- NGUYN L V NG DNG

H v tn: Lng Th HKhoa: Vt l Lp : Ak59MSSV : 595103019

H Ni 2011


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I.Lch s

Laser c phng theo maser, mt thit b c c ch tng t nhng to ra tia vi snghn l cc bc x nh sng. Maser u tin c to ra bi Charles H. Townes v sinhvin tt nghip J.P. Gordon v H.J. Zeiger vo nm 1953. Maser u tin khng to ra

tia sng mt cch lin tc. Nikolay Gennadiyevich Basov v Aleksandr MikhailovichProkhorov ca Lin bang X vit lm vic c lp trn lnh vc lng t dao ng vto ra h thng phng tia lin tc bng cch dng nhiu hn 2 mc nng lng. H th c th phng ra tia lin tc m khng cho cc ht xung mc nng lng bnh thnv th vn gi tn sut. Nm 1964, Charles Townes, Nikolai Basov v Aleksandr Prokhorov cng nhn gii thng Nobel vt l v nn tng cho lnh vc in t lngdn n vic to ra my dao ng v phng i da trn thuyt maser-laser.

Laser hng ngc, mt laser cht rn, c to ra ln u tin vo nm 1960, bi nh vl Theodore Maiman ti phng th nghim Hughes Laboratory Malibu, California.Hng ngc l xt nhm pha ln crm. Crm hp th tia sng mu xanh l cy v xanh

lc, li duy nht tia sng mu hng pht ra.Robert N. Hall pht trin laser bn dn u tin, hay laser diod, nm 1962. Thit b caHall xy dng trn h thng vt liu gali-aseni v to ra tia c bc sng 850 nanmt,gn vng quang ph tia hng ngoi. Laser bn dn u tin vi tia pht ra c th thyc c trng by u tin cng nm . Nm 1970, Zhores Ivanovich Alferov caLin X v Hayashi v Panish ca Phng th nghim Bell c lp pht trin laser diode hot ng lin tc nhit trong phng, s dng cu trc a kt ni.

II. Khi nim v lazer

Laser l tn ca nhng ch ci u ca thut ng bng ting Anh Light Amplification by Stimulated Emission of Radiation (S khuch i nh sng bng bc x kch hot)

Laser l ngun nh sng nhn to thu c nh s khuch i nh sng bng bc x phra khi kch hot cao cc phn t ca mt mi trng vt cht tng ng. Laser l sng c nhiu tnh cht c bit hn hn nh sng t nhin hay nhn to khc v cnhng cng dng rt hu ch c th p dng trong rt nhiu lnh vc khoa hc k thui sng, to nn c mt cuc cch mng khoa hc k thut sau khi n ra i.

S ra i ca Laser bt ngun t Thuyt Lng t do nh bc hc A. Einstein pht minra nm 1916. n nm 1954, cc nh bc hc Anh, M ng thi sng ch ra my

pht tia laser ng dng vo thc t. Cc th nghim laser trn ngi bt u t nhngnm 1960. T nm1964, bt u ng dng laser trong cc tr liu v Da (chuyn khoda liu).

1. Nguyn l pht sinh LASER:

Theo nhng khi nim c bn ca vt l lng t, khi ta chiu mt chm nh sng vomt mi trng vt cht (thut ng vt l hc gi l h vt l tng t) th chm nh


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s yu dn i do b hp thu bi mi trng vt cht. Bn cht qu trnh b hp thu y cc ht nh sng (photon) truyn nng lng kch hot cc phn t vt cht nhy ttrng thi n nh A ln mt trng thi B vi mc nng lng cao hn. V B l mt trthi khng n nh, nn sau mt thi gian nht nh, cc phn t ang mc B li nhv mc A v trong lc nhy v n cng pht ra mt photon mang nng lng bng

nng lng n hp thu, theo kiu vay g tr ny. l hin tng bc x. Tuy nhcc ht photon bc x ny khng nhiu, v n t l vi s phn t c mc B, m s pht trang thi B bao gi cng t hn s phn t trng thi n nh A. Cc photon bcx ny pht ra theo mi hng mt cch t do nn cn gi n l bc x t do. Khi ta lm cho cc photon tng tc bi cc phn t mc cao B, bt n tr v A smhn v pht sinh ra photon, cc photon c ng mc nng lng v ng bng mc nnglng cc photon ca ngun chiu truyn cho n th l bc x kch hot. Khi to ra bc x kch hot mc cao cho cc photon bc x pht ra lin tc mccao nht, ri c chn lc v khuych i chng pht v cng mt hng vi nh

tnh cht ging nhau ta s thu c chm sng laser. Nh vy nguyn l ca my phtlaser chnh l lm sao cho ngun sng chiu vo mi trng hot cht laser khng b yi c th kch hot lin tc cc phn t vt cht cho s phn t mc B lun nhiuhn mc A, nh vy s photon bc x s c pht sinh nhiu n mc ti a. Khi bng cc thit b c bit, ngun sng bc x ny s c chn lc v khuynh i pht ra mt chm nh sng n sc, gm nhng tia sng c cng hng, c bc snggn tng ng v c tp trung cao. chnh l laser.

2. Cu to my pht laser, bao gm cc b phn chnh:

- Hot cht laser: L mi trng cha cc hot cht c kh nng pht ra bc x laser khc kch hot bng mt ngun nng lng.- Ngun nui: L ngun nng lng duy tr hot ng ca mi trng hot cht lasgi cho hot cht lun lun trng thi c s phn t mc B nhiu hn mc A.- Bung cng hng: Bao gm 1 gng phn x ton phn v 1 gng bn m ( phn x t 70% n 99%)Bung cng hng cho php ngun sng kch thch cht nhiu ln v chm tia sng bx s c khuych i v chn lc qua gng phn x ton phn v gng m cho khi n nh pht ra chm sng laser.


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Cu to c bn v c ch hot ng ca laser.1) Bung cng hng (vng b kch thch)2) Ngun nui (nng lng bm vo vng b kch thch)3) gng phn x ton phn4) gng bn m5) tia laser

III. C ch

Mt v d v c ch hot ng ca laser c th c miu t cho laser thch anh.

Di s tc ng ca hiu in th cao, cc electron ca thch anh di chuyn tmc nng lng thp ln mc nng lng cao to nn trng thi o nghch mt ca electron.

mc nng lng cao, mt s electron s ri ngu nhin xung mc nng lnthp, gii phng ht nh sng c gi l photon.

Cc ht photon ny s to ra nhiu hng khc nhau t mt nguyn t, va phicc nguyn t khc, kch thch eletron cc nguyn t ny ri xung tip, sinhthm cc photon cng tn s, cng pha v cng hng bay, to nn mt phn ngdy chuyn khuych i dng nh sng.

Cc ht photon b phn x qua li nhiu ln trong vt liu, nh cc gng thiu sut khuch i nh sng.

Mt s photon ra ngoi nh c gng bn m ti mt u ca vt liu. Tia sngra chnh l tia laser.

IV. Phn loi laser: Ty theo loi hot cht laser ta s thu c cc tia laser vi tn gi khc nhau:


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Laser cht rn

C khong 200 cht rn c kh nng dng lm mi trng hot cht laser. Mt s loilaser cht rn thng dng:

YAG-Neodym: hot cht l Yttrium Aluminium Garnet (YAG) cng thm 2-5% Neodym, c bc sng 1060nm thuc ph hng ngoi gn. C th pht lin tcti 100W hoc pht xung vi tn s 1000-10000Hz.

Hng ngc (Rubi): hot cht l tinh th Alluminium c gn nhng ion chrom, c bc sng 694,3nm thuc vng ca nh sng trng.

Bn dn: loi thng dng nht l diot Gallium Arsen c bc sng 890nm thuc ph hng ngoi gn.

Laser cht kh

He-Ne: hot cht l kh Heli v Neon, c bc sng 632,8nm thuc ph nh sng

trong vng nhn thy, cng sut nh t mt n vi chc mW. Argon: hot cht l kh argon, bc sng 488 v 514,5nm. CO2: bc sng 10.600nm thuc ph hng ngoi xa, cng sut pht x c th t

megawatt (MW). Trong y hc ng dng lm dao m.

LASER cht lng

Mi trng hot cht l cht lng, thng dng nht l laser mu.

V. Cc tnh cht ca tia Laser :

- n sc cao

Laser l chm nh sng m cc tia sng ca n c mc chnh lch bc sng nh nht, vi cc chm sng n sc khc. S chnh lch bc sng ny cn gi l ph nh sngca chm nh sng.

V d nhin l ph cng hp th n sc ca chm sng cng cao. Trc khi c laser cc nh vt l to c cc chm nh sng n sc c chnh lch bc sng t 1Aon 10nm, nhng s dng trong nghin cu khoa hc. Trong khi mc chnh lch bc sng ca chm nh sng laser c th ti 0,1 Ao.

Tnh cht ny rt quan trng v hiu qu tc dng ca laser khi tng tc vi vt chtvi cc t chc sinh hc ph thuc vo n sc ny.

- nh hng cao

Khc vi cc ngun sng khc, cc tia sng Laser c chn lc ch pht ra nhng tiavung gc vi gng, nn hu nh song song vi nhau (hay ni theo ngn ng vt l lgc m gia cc tia l rt nh). Nh vy, laser c nh hng l tng, c th chiu


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rt xa, n mc ngi ta c th dng laser o nhng khong cch trong v tr. - Mt ph ( chi) rt cao

chi ca ngun sng c tnh bng cch chia cng sut ca chm sng cho rn

ca ph.V rng ca ph Laser rt nh nn laser c tp trung cc tia sng rt cao, hay nicch khc l chi rt cao so vi cc ngui sng khc.

V d:laser c cng sut thp l laser He-Ne cng c chi gp hng vn ln chica nh sng mt tri. Nhng laser c cng sut ln c chi cao gp hng triu lnmt tri.

- Cng sut ca laser

Ty loi laser m c ngui sng cng sut khc nhau. C nhng loi laser cng sutmnh tng ng cng sut 1 vn nh my in 1 triu KW. Nhng ngun laser cnsut mnh c th s dng trong cng nghip nng nh khoan ct vt liu, hay ch tcc loi v kh, kh ti qun s.

Cc loi laser s dng trong y hc l nhng laser c cng sut thp nh laser He Necng sut ch khong t 2MW n 10MW.

5. Nhng cng dng ca laser: Ngy nay, ngi ta ch to ra c gn 500 loi laser khc nhau, ng dng trong r

nhiu lnh vc:- o c nhng khong cch cc ln, nh trong nghnh thin vn (o khong cach t trt n cc hnh tinh v khong cch gia cc hnh tinh trong v tr).- Thit lp dn ng nh cc loi bom, tn la c dn ng bng laser.- Thng tin lin lc- Cng nghip nng: hn ct kim loi- Cng nghip ch to v kh.- Ci to ging- Trong y hc (chun on v iu tr bnh, sn sc thm m)

VI : Cc ng dng ca tia lazer1 . ng dng ca laser trong nghin cu khoa hc:

a. Nghin cu v Quang hc phi tuyn:

Nh chng ta bit trong quang hc c in cc ngun sng pht sng l nhnngun khng kt hp v c cng nh. Khi tng tc ca nh sng vi cc mi tr


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vt cht, phn cc ca mi trng ch l hm tuyn tnh ca cng in trngsng ti.

P = E y, P l phn cc ca mi trng.

l cm in ca mi trng.

E l cng in trngKhi cng sng ln nh c bc x laser th ta c th biu din li phn cc sau:

P = ...33

2

21 E E E ++

Khi E cng ln th s hng bc cao ca E cng tr nn c tc dng ln v chng dn nhng hiu ng mi trc y khng quan st c, l cc hiu ng quang phi tuy Ngy nay ngi ta nghin cu k lng c trn phng din l thuyt ln thc nghiv cc hiu ng quang phi tuyn, m ra mt ngnh khoa hc mi l ngnh Quang hc ptuyn vi nhiu hng nghin cu khc nhau v ng dng khc nhau lnh vc ny.

b. Holography:Holography l tn thng gi ca chp nh khi. Nguyn l ca holography c

xut nm 1948 nhng do ngun sng chp khng mnh nn khng thu c kqu. Ch t khi c laser, ngi ta s dng ngun sng ny thu c nh khi cvt v nghin cu v holography c pht trin rt nhanh v tr thnh mt ngnh khhc ring trong vt l v quang hc k thut.+ Holography l mt phng php ghi hnh nh phng php chp nh nh my nTuy nhin n c nhng u im ni bt hn phng php chp nh thng thng.

- Phng php ny chp nh khng cn thu knh.- N cho hnh nh khi ca vt, ngha l cho hnh nh 3 chiu.- Holography ghi li cc sng tn x t vt bao gm c bin v pha ca sng v bt c im no ca Holography cng c cc tn hiu t ton vt chp . Do vy, nnh ta b gy Holography tanh nhiu phn th mi mnh nh cng vn c nhng thng tin ca sng tn x t vt v cho ta hnh nh c vt khi phc hi. ymt c tnh quan trng ca Holography c th c c nhiu bn sao chp cvt , d bo qun v nhn ln.- Do holography c hnh khi nn n c th ghi li tn hiu t cc vt khc nha

trn cc vng khc nhau, ngha l c th cng mt lc gi li nhiu thng tin.+ Vi nhng u im nh va nu trn th hin ti ngi ta ang v s m ra nhing dng th v v quan trng nh sau:- Nu ngi ta ghi li mt lng thng tin ln mt yu t th tch ca holograp

th n c th tr thnh b nh tt nht cho my tnh. V n c ghi li v phhi bng nh sng nn dn ti vic xy dng cc my tnh in t quang hc. vi loi my tnh ny th tc x l thng tin nhanh gp nhiu ln my tnh hic do trong my tnh quang hc tc lan truyn tn hiu l vn tc nh sngtrong mi trng.

- Khi s dng cc loi nh sng khc nhau ghi li Holoraphy th khi phc h bng nh sng trng ta c th thy c hnh nh mu ca vt. ay chnh


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nguyn tc chp nh mu v video mu. V trong tng lai th k thut chp ntruyn hnh ni v mu rt c trin vng.

- V holography cho ta hnh nh khi vt nn ngi ta c th s dng mu kitra sn phm nh lp t khi so snh vi mt lp chun xem c sai hng gkhng.

- Nh phng php ny ngi ta d dng ghi li hnh nh khi ca cc sinh vnh khi chng ang chuyn ng hoc ngay c tn la, my bay khi chng angchuyn ng c th nghin cu s thay i theo thi gian ca cc vt trn thenhng mc ch nghin cu khc nhau.

c. Nghin cu plasma nng v cc phn ng nhit hch: Do tia laser c tnh cht l cng sut cao, ch pht xung c th t c cn

sut c 1012 1015 W nn khi bn tia laser vo vt cht c th to ra c plasma nhi cao. V nhit cao ny s c cc phn ng nhit hch, t y m ra kh nnghin cu phn ng nhit hch c iu khin c trong phng th nghim.

d. Nghin cu sinh ha hin i:Trong cc phn ng ha hc khi c d tham gia ca nhiu ng v ha hc thn

gp kh khn khi ta mun loi tr nh hng ca ng v no trong lin kt. Tunhin, do cc ng v c nng lng lin kt ha hc sai khc nhau t nn ch c nh tilaser c n sc cao mi d dng ph hy lin kt no khi c s tng tc chng. Nng lng bc x laser hf s ph hy ch lin kt no tng ng vi nng lny m khng nh hng n cc loi dao ng vi tn s f 1, f 2, f 3,khc rt t f. Ngita ni rng ay chnh l s ph hy hay kch thch chn lc phn ng ha hc. Chnh iny m ra kh nng nghin cu cc sn phm trung gian ca ha hc, nghin cu qutrnh din bin theo thi gian ca phn ng, y l iu m khoa hc m c t blu nay. Cng chnh nh c laser m cc nh khoa hc cn c th nghin cu c phng trng thi kch thch.

2. ng dng ca laser trong khoa hc k thut:

C th ni y l lnh vc rng ri ca s p dng laser v ang c nhiu kt qu l th

a. Trong thng tin lin lc:

V laser c tnh cht l n sc cao v tnh kt hp cao nn laser c s dnrng ri v nhanh nht trong ngnh thng tin lin lc.S dng tia laser c nhng u im sau:So vi sng v tuyn di sng truyn tin ca tia laser ln gp bi v d vi sng v tuytn s s dng l 104 3.1011Hz nn di sng truyn tng ln n 5.104 ln. Do , cc bc x laser nm trong khong 0,4 0,8m v vi mi knh truyn tin l 6,5 MHz ths dng laser ta c th c gn 80.105 knh truyn cng mt lc v gp 105 ln knhtruyn khi s dng sng cc ngn.


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Ngoi ra, do tia laser c tnh cht l mang nng lng ln nn n c th i xa hn csng v tuyn. Do nu s dng tia laser th gim c hang t ln nng lng cn duV vy, tia laser c s dng trong truyn tin trong v tr.

V nu s dng cc bc sng thch hp c th truyn tin cc mi trng khnhau nh trong sng m, di bin

b. Trong nghin cu v tr:

Tia laser c s dng rng ri trong nghin cu v tr, v d nh:- Tia laser c s dng xc nh v tr cc vt th trong v tr.- Theo di cc tu v tr v lin lc vi chng.- iu khin cc tu v tr.

3. Trong cc ngnh khoa hc khc:

a. Trong cng ngh gia cng kim loi:

Da vo tnh cht tia laser c cng ln nn c th khoan, hn, ct, gt kim loTia laser c ng knh nh nn c th thu c cc l khoan c ng knh c bsng khoan c nhng kim loi cng nh bch kim, hng ngcVi cc laser xucng sut ln vic gia cng kim loi c tin hnh nhanh v hiu sut cao nn ngy nn c s dng rng ri trong cc cng on khc nhau.

b.Trong o lng tiu chun:

Tia laser c n nh v tn s tr thnh thc o chiu di chun. Cc bc ca laser Cd lm tn s chun, bc x ca laser He - Ne o tc ca nh sng

c. Trong kh tng :Dng tia laser c th o c nng cc ht hi nc trong cc m my d

on thi tit. Bng cch th cc bng thm khng trc y, vic xc nh thi tithng lu v tn km. d.ng dng ca lazer trong y hc

Khi chiu tia sng laser vo mt h sinh vt nh c th con ngi, s c nhng hiu sinh hc xy ra trong c th. Nhng hiu ng sinh hc ny l c s s dng laser try hc phc v con ngi.

Khi s dng laser iu tr th yu t quyt nh hiu qu l liu chiu, bao gm cctham s:- Cng sut- hi t (mt cng sut )- Thi gian chiu- S ln chiu- Khong cach gia cc ln chiu


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Bn cnh c im ca t chc c th ni chiu cng l yu t quan trng gp phto nn kt qu tt trong iu tr. Cc ng dng c bn ca laser trong y hc:

1. Trong chun on, c nhiu thit b chun on s dng laser nh :- My Dopler Laser thm d, o dng mu trong c th.- My chp ct lp laser.- Cc my d tm, o c, dn ng trong chun on.

2. Trong iu tr:

ng dng ca laser trong iu tr rt phong ph:

- Da liu: ty xa cc u, mn, cc m sc t nh nt rui tn nhang, cc bt bm

sinh vv- Nhn khoa: rt nhiu ng dng nh iu tr hn gn cc tn thng vng mc,iu tr cc tn thng gic mc, trong cc phu thut sa cha cc tt khc xca mt v phu thut iu tr cc bnh l khc ca mt.

- H thng tiu ha: tn si ng mt ch, trong cc th thut ngoi khoa iu tr cc khu ng tiu ha, trong to hnh thc qun, trong vic hn gn cc tn thng mch muni tng nh trong cc trng hp ung th, vim lot ng tiu ha, v..v...


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- Sn ph khoa: iu tr cc tn thng bnh l c t cung trnh nguy c ung th h- Tai Mi Hng: iu tr cc tn thng ca dy thanh m, cc bnh l v tn thnvng hng hu.- Thn kinh: iu tr cc tn thng dng u do h thng thn kinh.- H hp: iu tr cc khi u phi, cc tn thng bnh ly khng phi do u, v hn gn

cc tn thng kh qun do t ng ni kh qun khi gy m hay do th thut m khqun cp cu.- Tim mch: ph hy cc mng x va thnh ng mch. A. Dao m laser:

Ngi ta s dng cc laser nhit phu thut nh mt dao m bng tia sng laser. ihnh l dao m bng laser CO2. Khi chiu tia laser, t chc c th ni tia i qua s bayhi rt nhanh to nn mt ng ct st nh dao. Do tc dng ca nhit, hai bn nct s s hnh thnh ct hng ro sinh hc bo v vt m nn vt m rt v trng vkhng b chy mu. V chm tia laser CO2 khng nhn thy nn trong my pht laser ph

gn thm laser He Ne cng sut 1-2 mw pht tia mu dn ng. Nhng u im ca dao m laser:

v khun cao v laser to nhit cao ti ng rch v khng c s tip xc giadng c v c th. Laser CO2 c kh nng va rch ng m va cm mu. To ra hng ro sinh hc bo v chung quanh ng rch.

t gy tn thng cho cc t chc ln cn vt m.- Thi gian m ngn hn.- Sn sc hu phu thun li hn.- Ap dng thun li trong nhng trng hp madao m thng t hiu qu. c bit, dao m laser c s dng phu thut nhng b phn su trong c thkhng lm tn thng nhng phn c th n i qua. N ch tc dng chn lc trn phm t chc nh sn. Nh l phu thut cc tn thng, cc khi u s no, ty sng, pthut mt vv.

B. Laser l phng tin iu tr t xm ln:

Khi chiu laser vo t cha c th mt nhit nht nh, laser s lm ng protein t chc. Hiu ng ny c p dng can thip iu tr t xm ln cc tn thng cc th k c can thip su vo bn trong c th. Do mi loi laser c hi t khc nhau v mi loi t cha m c th c kh nng hthu khc nhau nn ngi ta da vo tnh ton liu chiu v cch chiu sao cho lasch tc dng chn lc ti mt ni theo s dng.


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Kh nng ny c ng dng trong nhiu chuyn khoa y hc nh Mt, Tai - Mi -Hng, phu thut thn kinh s no, phu thut ph hy cc khi u trong c th. K cthng bn ngoi c th nh u mu, vic s dng laser ph hy khi u l phng piu tr ti u.

C. Tc dng kch thch sinh hc: C rt nhiu loi laser cng sut thp c s dng khai thc kh nng kch thch cqu trnh sinh hc. Nhiu cng trnh nghin cu cng nh thc t ng dng lm sng cho thy hiu ng kthch sinh hc khi chiu laser c rt nhiu ng dng mang li hiu qu cao trong cngvic phng bnh v cha bnh, duy tr sc khe con ngi. Chiu iu tr vt thng:

+ St trng vt thng+ Tiu hy cc t bo m cht+ Tng cng chng vim, gim au+ Tng sinh cc m lnh+ Kch thch t chc ht vt thng pht trin nhanh+ Thc y nhanh qu trnh lnh so v hi phc chc nng

Chiu kch thch t chc lnh:

+ hi phc v tng cng sc khe+ duy tr v tng cng hot ng sinh l bnh thng ca cc c quan trong c th+ iu chnh cc ri lon v tng cng hot ng ca h tim mch

+ Duy tr chc nng bnh thng ca cc hot ng tm thn kinh+ Chm cu bng laser + Tng lu lng mu n nhng vng c chiu

e. ng dng ca lazer trong thm m

Cng trn c s nhng hiu ng sinh hc ca laser v nhng ng dng ca laser trong hc, chng ta nhn mnh thm nhng ng dng ca laser trong thm m. Trong thm m s dng laser theo 2 hng: Gii phu thm m v sn sc thm m (Nkhoa thm m). c s dng ph bin v hiu qu cao nh LASER CO2, ND- YAGErbium,Q-Nd, Fraxel, V-beam, Ruby, laser kt hp CO2 erbium/YAG, vv

1. Trong gii phu thm m: thng s dng laser nhit nh mt con dao m, ph binht l laser CO2, laser Argon v laser YAG.

- Trong gii phu dng laser ct nh mt con dao m vi s dn ng ca laser H Ne c rt nhiu u im nh ni phn trn.- iu tr so mn trng c


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- iu tr cc u mu- iu tr cc u sc t- t, ty cc nt rui xu- t mn tht- Ty tn nhang

- Ty vt nm- Bt bm sinh- Lt da mt cc mc khc nhau- Ty lng- iu tr so li, so ph i- Cc vt tham sc t sau phu thut

2. Trong sn sc thm m:

Nh ni phn trn, nhng ng dng ca laser trong sn sc thm m cng da trnnhng hiu ng sinh hc m ch yu l hiu ng kch thch sinh hc ca laser khi chivo t chc m c th ngi. Laser s dng trong sn sc thm m ch yu l laser lnh, cng sut thp. c bit, laser c s dng ngy cng ph bin trong cc k thut chm sc da trongqu trnh tr ha da (Rejuvenation). Cc k thut tr ha da thuc 3 nhm theo c th khc nhau l:- C hc (cc dng c mi da)- Ha hc (dng cc loi ha cht)- Nhit (dng cc loi nh sng c nng lng cao nh laser)

Hay cn gi l phng php chm sc thm m da bng nh sng ang rt c tin dnv ngy cng ph bin trn th gii. Tt nhin nh ni trn, vic s dng laser i hi phi nm vng k thut v thn


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tho c ch nh chnh xc v liu chiu, ni chiu v phng php chiu, nhm hiu qu cao nht vi s an ton tuyt i. C nhiu loi laser c d dng v chng c nhng c tnh khc nhau (bc sng,cng sut, mt cng sut ) v vy , mi loi laser s dng cho nhng phn da kh

nhau (tc dng chn lc) vi liu chiu khc nhau. Ngoi cc cng dng nh ni phn ng dng trong gii phu thm m, laser cn dng sn sc da thun ty vi ck thut:

- Ty t bo cht trn da- Chiu kch thch cc t bo da pht trin v thay mi- Kch thch tng cng tun hon di da tng nui dng da v lm hng ho da- Kch thc tng sinh, ti to collagene v m m da cng y v mm mi- Lm tng n hi ca da xa cc vt nhn- Chng lo ha da- Gi gn sc din ti tr cho da

- Lm tan m nhng vng ng m khng mong mun- Lm sn chc nhng b phn b nho, x- Hi phc v duy tr vc dng tr trung ca c th

Cn lu : Laser c nhiu ng dng hiu qua trong y hc ni chung v thm m niring, nhng vic s dng laser trong thc t i hi s hiu bit y v tun thnghim ngt cc qui nh v ch an ton cho c bac s v bnh nhn. Ngy nay, cc nc tin tin ngi ta ch to ra nhiu my pht nhiu loi laser khc nhau dng trong thm m.Cc my laser hin i u c chng trnh(computerized) nn rt tin li cho vic s dng.

Vit Nam, t hng chc nm qua, laser c ng dng trong y hc ni chung vtrong gii phu thm m cng nh sn sc thm m ni ring, nhng ngi hnh nghtrong lnh vc thm m cng lun cp nht nhng tin b ca th gii v tip thunhanh chng cng ngh mi s dng c hiu qu trong thc t. Tuy nhin, laser lcng ngh tin tin nn gi thnh cc thit b laser cn cao v cng l mt ro cn chvic ng dng laser phc v con ngi. D vy, nhiu loi my laser thm m tin tin c mt ti vit nam phc v kp nhu cu lm p ca ngi Vit Nam. Hy vng cng vi s hi nhp ca t nc v pht trin nhanh chong ca nn kinh t ton cu, ngi Vit Nam chng ta s nhanhchng c c hng kp thi nhng tin b khoa hc k thut trong cuc sng nichung cng nh trong lnh vc chm sc sc p ni ring.

4.ng dng mi ca laser.

a. ng dng laser to ra v kh ht nhn:


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V kh laser khi c bn ra, tuy khng c n nh sng pho thng nhng li phra chm tia laser nng lng cao vi tc 300.000 km/giy. Nng lng ny tp trungrt mnh, khi chiu vo vt th kim loi, trong nhy mt s lm cho kim loi nng ch bc hi, thm ch bin thnh ion.

Tc dng gi l hiu ng lan chy nhit. V kh laser ph hoi mc tiu ch y

nh vo hiu ng . Chm tia laser gy tc dng lan chy cng ln hn i vi c thsng, thm ch gy t vong. Cho nn tia laser tng c mnh danh l tia cht chc. Nu bn a knh hi t ra trc nh nng ly tiu im sng. Tiu im ny c

lm chy giy. Vy m sng ca tia laser cn cao gp vi trm triu, thm ch vi tln so vi nh nng Mt tri. Nng lng ca n d nhin l rt ln. Do , ngi ta dng v kh tia laser bn my bay, tn la ca i phng. Ngoi ra, khi bn vo mtiu dng kim loi, tia laser cn sinh ra tc dng ph hoi ph. l dng ion hnh thndi nhit cao ca tia laser khi pht ra khi b mt kim loi, lc phn tc dng s g ph ti xung kch trn b mt kim loi, lm bin dng, ph hu nhanh chng vt th.ng thi dng ion cn pht ra bc x X, lm cho cc linh kin in t gn mc tiu bv hiu ho.

Mt iu cn phi ni thm l, chm tia laser cn lm cho ngi ta b m mt hoctm thi khng nhn thy g. l v mt ngi ging nh mt thu knh hi t, khi bchm laser chiu vo qua hi t ca thu tinh th s hnh thnh tiu im trong vngmc, lm cho nng lng laser cng tp trung hn. T chc vng mc cc mng b hpth nng lng ln ca tiu im nh sng, s nhanh chng chuyn thnh nhit nng lchy bng vng mc, dn n m mt.

b.Tia laser phng tu v tr

Khi rung ng, tia laser t nng khng kh cho n khi chy. Mi ln khng kh chy

li to ra mt tia sng lo ln. thot khi sc ht tri t, lu nay, loi ngi vn s dng tu con thoi, loi tu phi mang theo hng tn nhin liu v hai tn la y ln. Nhng khng lu na, cc cotu v tr s lt vo khng gian trn mt chm tia laser, cn rt t hoc khng cn chn y v khng h gy nhim.

tng c bn ng sau k thut y bng nh sng l s dng cc tia laser t mt t nng khng kh n mc lm khng kh n tung, y con tu tin ln pha trc Nu thnh cng, k thut y bng nh sng s lm con tu nh hn hng nghn ln, hiqu hn so vi cc ng c tn la s dng cht ho hc v khng gy nhim.

Chng ta s xem xt hai kiu h thng y tin tin: mt kiu c th a chng ta ttri t ln mt trng ch trong vng 5 gi ri v kiu kia c th a chng ta du lch hmt tri trn cc xa l nh sng.

nh sng rc r l khng kh ang chy di vnh tu.Tu v tr nh c y bng laser. Nguyn l rt n gin: con tu s dng cc tm

gng thu nhn v hi t chm laser chiu vo, ri t nng khng kh n khnkh n tung, y con tu i.

Di y l cc thnh phn ca h thng y mang tnh cch mng ny.- Tia laser carbon dioxit: Tia laser xung 10 kW ang c s dng th nghim con tnh ny l mt trong s nhng tia mnh nht th gii.


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- Gng parabole: Phn y ca tu v tr l mt gng hi t chm laser vo khoacha khng kh hay cht n y trn tu. Vt truyn th hai, nm trn mt t, l mtgng ging nh knh vin vng c dng hng chm tia laser ln con tu.- Khoang ht thu: Khng kh c hng vo trong khoang ny; ti y khng kh b

nng ln bi chm laser, gin n ra v y con tu i.- Hydro trn tu: Mt lng nh cht n y hydro c s dng y tn la khi kquyn qu long khng th cung cp khng kh.

Trc khi bay ln khi mt t, mt lung khng kh nn s y nh con tu ln nvn tc khong 10.000 vng/pht. Khi n ang ln xoy vi mt tc ti u, tia lass c bt ln, thi con tu ln khng trung. Tia laser 10 kW ny rung ng mc t25-28 ln/giy. Bng cch rung ng, n lin tc y con tu ln pha trn. Chm tia snc hi t bi gng parabole y ca con tu t nng khng kh ln ti khong t10.000-30.000 C, nng hn b mt ca mt tri vi ln. Khi khng kh b t nng nhit cao nh vy, n s bin i sang th plasma (loi kh c s lng cc ht main m, dng, tng ng nhau trn mt tri v phn ln cc v sao) th plasma n

sau n tung y con tu ln pha trn.Ngoi ra, ngi ta cng s t cc gng bn trong con tu chiu mt s chm

nng lng v pha trc. Sc nng t chm laser s to ra mt cm kh lm chchhng i ca mt phn lung khng kh i qua con tu, t gip gim bt ma st vgim lng kh nng m con tu hp th.

c. Thit b iu khin bng laser gip ngi tn tt i li

Cc nh nghin cu thuc i hc Virginia (M) ang th nghim mt mu thit bdnh cho nhng ngi ln tui khng c kh nng i li. Thit b ny c hnh dng t

t nh xe y tay ca tr con, c cn li v phanh xe bng in c iu khin bnglaze.

Thng qua ng c gn km, cc tia laser gip nhn bit quang cnh xung quanh ngiiu khin, d on hng di chuyn ca h kp thi b li bnh xe trc ng thkp cht bnh xe sau. Nu pht hin c vt cn, xe s t ng b li trnh sang mt b Ngi iu khin xe s khng s ng v c phanh xe t ng. Cc nh nghin cu hyvng sp ti h s thit k thm cho xe chc nng nhn bit ging ni con ngi.

d. Chic ng h chnh xc nht th gii:

S dng cng ngh laser phc tp v mt n nguyn t thu ngn, cc nh khoa hM to ra chic my o thi gian chnh xc gn nh tuyt i, vi sai s 1 giy tronc cuc i ca v tr - khong 15 t nm.

Cc nh khoa hc ti Vin Tiu chun v Cng ngh quc gia Boulder, Colorado, pht trin mt loi ng h nguyn t mi c th tc tc mt triu t ln trong mi gchnh xc gp 100-1.000 ln so vi cc ng h vi sng xezi hin nay. Chic ng hny c gi l ng h nguyn t quang hc, v n p dng cng ngh laser, o nhng


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khong thi gian ngn nht tng c ghi nhn ti nay. Nguyn l lm vic tng t ncc loi ng h nguyn t ra i t thp k 50, nhng thay v vi sng, n s dng nhsng quang hc c tn s cao hn, cung cp thi gian chnh xc hn.

Tng lai, loi ng h ny s ng vai tr quan trng trong nhiu lnh vc cn

chnh xc cao nh cc thit b v tinh, Internet, phn phi in, nh bnge. My laser ln nht th gii

Trong khong thi gian bng 1/10 t giy, my siu laser Jena s phng ra mt ngunnng lng bng tng nng lng ca tt c cc nh my in trn th gii cng li. s l mt bc tin ln nht trong lch s ng dng laser.My c xy dng theo m hnh hin i, gm 4.500 it laser mc song song vi nhaTrong mi it s c cng sut tng ng vi 100.000 ln cng sut ca my qulaser dng trong a CD hin nay.Khi ra mt my laser Jena s c cng sut 1.000 t Watt!

Khi nghin cu sn xut my laser Jena, Sauerbrey cn t c mt k tch khnggian khc. Trong khi cc my phng laser c cng sut ln hin nay phi cn mt dintch tng ng vi c mt sn vn ng, th my siu laser Jena ca ng c t trmt phng th nghim vn vn c 200 m2!

My siu laser Jena s ng gp ln cho vic sn xut ng v phng x dng chochn on y hc v tr liu bng tia X. Mt khc, vi cng siu mnh, my c thgip kh x cht thi nguy him. Hin nay, cht thi loi ny c x l bng cch btrong v ch, sau chn su xung lng t hoc th xung y bin.

f. Cu ni laser gia cc v tinhLn u tin, hai v tinh khong cch trn 30.000 km trao i thng tin c v

nhau thng qua mt chm laser. K thut ny cho php cc v tinh qu o thp githng tin nhanh chng v n nh xung trm x l di mt t thng qua mt v tinha tnh qu o cao hn.

Trong th nghim ln ny, cu ni laser (laser link, l mt chm laser c ng knhvi mt) c th truyn cc d liu v hnh nh vi tc 5 megabits trong mt giy.Hin cc nh khoa hc ang pht trin mt ng truyn mi c dung lng ln hnnhiu, cho php truyn c m thanh v hnh nh. Cc nh khoa hc s dng h thnlaser c tn l SILEX (do C quan V tr chu u ESA v C quan V tr Php CNEStrin khai) ni v tinh Artemis vi v tinh thin vn SPOT 4. Chm laser ny ciu chnh tinh vi, cho php SPOT 4 chuyn lng d liu ln vi tc nhanh tiArtemis.

Artemis bay qu o a tnh, cch tri t 31.000 km, trong khi SPOT 4 di chuynvi tc 7.000 m/s cao 832 km. Bi vy, cu ni laser phi c thit lp rtchnh xc. Theo ng Oppenhaeuser, ng truyn laser gn hn, chc chn hn v cn nng lng hn h thng thu pht sng v tuyn. Vic gi thng tin t cc v tinh qu


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cc nguyn t kh lnh. V nguyn tc, cc nh khoa hc c th m ha thng tin tronxung sng lu gi v s dng. V th, th nghim ln ny l mt bc tin mi tng tm kim y l ln u tin ngi ta c th gi mt xung sng, iu chnh tnv di chuyn n gia cc nguyn t kh lnh. V nguyn tc, cc nh khoa hc c th mha thng tin trong xung sng lu gi v s dng. V th, th nghim ln ny l m

bc tin mi trn ng tm kim b nh l tng cho my tnh lng t.i. ng c lng t bin kh thi thnh laser

Lung kh thi nng hi thot ra t ng x khng hn l tha v dng. Ngi ta th li dng nguyn l c hc lng t chuyn chng thnh nng lng c li ddng bc x laser. Nh vt l Marlan Scully, i hc Texas A&M (M), thng bo.

Scully ni rng, s dng kh thi t ng x ca ng c bn k, ngi ta cn mng c lng t ph (quantum afterburner). ng c ph ny hot ng theo nguyn c hc lng t, ti s dng nhit lng tha ca kh thi chuyn thnh nng ln

hu ch di dng bc x laser, nhm nng cao hiu sut ca ton b h thng.ng c lng t ph ca Scully gm hai thit b: mt to ra laser v mt to ra

maser (tia maser l mt loi tia laser vi bc sng siu ngn, ngn hn bc sng nhsng thng). Bnh thng, trong kh thi nng, s lng ht t l nghch vi mc nnlng ca chng. Ngha l, ht c mc nng lng cng cao th mt ca chng cngnh. Tuy nhin, khi i vo thit b laser, cc ht trong kh thi b kch thch, lm s lnht cp nng lng cao tng vt.

ng c lng t s dng cc ht kh thi ba trng thi khc nhau (3 cp nnglng). Thit b maser y cc ht b kch thch cp nng lng th hai ln cp cao

nht. Qu trnh ny lm tng mt cc ht nng lng cao gia bc hai v bc mt.Chnh cc ht ny to ra bc x laser.

Tm li, vi vic gn thm mt ng c lng t ph, nhit lng ca kh thi chuyn thnh bc x laser, gp phn nng cao hiu sut ca ton b h thng. Ngc trong mt ng c bn k bnh thng, nhit lng ca kh thi khng dng c na

Scully v cng s ang th lp t mt ng c lng t thc s kim nghim tng ny.

k. Trng thi th t ca vt cht:

Vt cht, ngoi ba trng thi thng gp l th rn, lng, kh, cn tn ti mt dnc bit khc, c gi l "trng thi plasma", hay l th kh ion ho.

Hy ly nc lm v d: un nng mt cc bng n mc nht nh, n ( th rs bin thnh nc (th lng), nhit tng ln na nc s bc hi (th kh). Nu titc tng nhit nc ln cao na, kt qu s l g?


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Khi nhit cht kh cao hn vi ngn , cc electron mang in m bt u bt khnguyn t v chuyn ng t do, nguyn t tr thnh cc ion mang in dng. Nhit cng cao th s electron bt ra khi nguyn t cht kh cng nhiu, hin tng ny gi l s ion ho ca cht kh. Cc nh khoa hc gi th kh ion ha l trng thi plasma. Ngoi nhit cao, ngi ta c th dng cc tia t ngoi, tia X, tia bta cc

mnh chiu vo cht kh cng lm cho n bin thnh plasma.Khng phi l xa l

C th bn cm thy trng thi plasma rt him gp. Nhng thc ra l mt trngrt ph bin trong v tr. Trong lng phn ln nhng v sao pht sng u c nhit p sut cc cao, vt cht y u trng thi plasma. Ch c mt s hnh tinh ti vvt cht phn tn trong thin h mi c th tm thy cht rn, cht lng v cht kh.

Ngay xung quanh chng ta cng thng gp vt cht trng thi plasma. Nh tronng n hunh quang, n neon hay trong h quang in sng chi. Hn na, trong tng

ion xung quanh tri t, trong hin tng cc quang, trong kh phng in sng chi kh quyn v trong ui ca cc sao chi u c th thy trng thi k diu ny.

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