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Hafod Laser Spectroscopy
0) Laser — in duced Fhucrescence (LCF)
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OQ Absorption PrMersfy
Sy Sigqrel al
leader
detector
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KL
Advantages f LIF
low backgroud phe fecurrent ef
tow ba ckeg rowel noise. ~My
> suitable for detecting wea Je Sigoal ¢ From Very smal]
hum bers atmo.
Advantages for gqbhsorption spectrascepy _
Fer tases in which eptrcell depth ake, absorp tion 's
more fensiAve than Fluorescance Che. Ca, measure
hum barr f absor bin atoms fn kss cuewag hg tine)
Essentially this is Aue to fact that fr ele each
absorbed Phsta. results in only a Pordba bility ~ enn
‘
i having 9 detected plete, whereas va “absapiion
Spectre Scopy each yhoten Is detectd as a “missing "
ho tims Cron, The detected lager Leamr-
Alse, abcerp tom Spe ctroscopy is shy hrly 2a 6 hem
to set Sh
Absorption in a ges — Doppler breadened Hii iba
[Similay to what we discussed earlier in classical
except Ge Satura ery effects )
won,
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=Pe -.
== — Ia p
Rue
—l— |b>
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LK orden +o talee enaatawtae i haf oenee tie f
{osena, sh FS neces to find methods fo remove
Dopp ba effect. Mest commen methods |
(©) Atomic bean spechoscory
ler Free Spe.
aa bere diver,
1 — 1 . ae
ae TE
et ladon L ecu
A narths ete
(Cx n be )
Deppler shite ev oO => Depp lepoGee.
residual Deppler width - &
eg ke x | Ge ar 107
an
Px wi dite
© Twexphoten spectrscopy _
: Doppler shift
ve } -é2s Pons) Hor is aie hwo °F osu:
maps ya re ° a ley die. ia enp
Ty se PK
vo, By
2 ° Two ~photon reson \,
ia D= 2w,—- (wr -kyv) —(wrky)
Ly, F; Zi 0
Is Oy = = 2W,y~ ZW a jy be
shitth.
@ Saturation Cine) Spee
Pee I<Ts plimp _leten LL. 2 Te
probe absorption coefficie +e
Since probe Tels) probe has Title ellect om
populations q(x) and 7,Cx), Pump becn dees
affect populations. Hence
oo
% =f fro -7,0)) CN dx
ee el An
-® populations crosS- Section boy probe bea .
established by has opposite Deppler
pump beam chif+ te pumy bean ,
Com Show? _
(, 2)
Xe = i GS (A) Pi ae S Bor (we/2 A
Ww = a it A EE = owt — broadtued
: ( Fs ) P Jin-ew folHe,
f= i eee
Siem (1441+ Fa)
Sub- Doppler resglubion ) with
on" In { et fect
x)
opal ati cpulation
it i) ies
1 phe.
Cele fob .
A
W, ¥ 2
= lo MHe, net 16He-l
faba of wie, Sant
populations -
3 decreased probe
absovy tim Oo
exact vesenentee,
b=-O0. (due te
Shura Coiaced
ge eS
