ICLAS of Water Isotopologuesnear 12000 cm-1
Laboratoire de Spectrométrie PhysiqueUniversité Joseph Fourier de Grenoble (France)
Fabio MazzottiAlain Campargue
Samir Kassi
Water Isotopic Abundances
0.031069HDO
0.0372 H217O
0.199983H218O
99.7317H216O
Abundance (%)Isotopologue
P. De Bievre, N.E. Holden, and I.L. Barnes, J.Phys.Chem.Ref.Data 13, 809-891 (1984)
1x10 -28
1x10 -27
1x10 -26
1x10 -25
1x10 -24
1x10 -23
1x10 -22
1E-28
1E-27
1E-26
1E-25
1E-24
1E-23
1E-22
11500 12000 12500 130001E-28
1E-27
1E-26
1E-25
1E-24
1E-23
1E-22
HITRAN
H2
18O
Inte
nsi
ty (
cm/m
ole
cule
) fo
r p
ure
H21
8O
Kitt Peaks FTSTypical ICLAS
Sensitivity
Wavenumber (cm-1)
SP 2000
1 1 0 0 0 1 1 5 0 0 1 2 0 0 0 1 2 5 0 0 1 3 0 0 01 E - 2 8
1 E - 2 7
1 E - 2 6
1 E - 2 5
1 E - 2 4
1 E - 2 3
1 E - 2 2
Inte
nsit
y (c
m/m
ol)
W a v e n u m b e r ( c m - 1 )
H216O: region of interest
absorber
l
α
v
Principle of Intracavity Laser Absorption SpectroscopyPrinciple of Intracavity Laser Absorption Spectroscopy
emission spectrum
I
ν
laser cavity L
mirrormirror
ν
?
laser gain
with c: speed of light , tg: generation time
Leq= c tg l/L
1200012020
12040
12060
12080
12100 50
100
150
200
Lase
r In
tens
ity
Generation time ( µs)
Wavenumber (cm-1)
Spectral dynamics of ICLASSpectral dynamics of ICLAS
I (v, tg) = e-α Leq
300 µs ⇒ 36 km !!!
αmin ~ 10-9 cm-1
Leq= c tg l/L
∆−−
∆ gg ?t
?tJ 200 exp
ννν
πν
l/L˜ 0.4
∆tgtg
Ar Laser AOM 1
Absorption Cell
2.0-meter Grating SpectrographCCD
AOM 2
CrystalOutput Coupler
Ti-Sa Laser Cavity
Pump Beam
ICLAS Setup
Spectrum acquisition
1400 1500 1600 1700 1800 19000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Inte
nsit
y (A
.U.)
CCD channel number
Water vapor (16 Torr)
1400 1500 1600 1700 1800 19000.0
0.2
0.4
0.6
0.8
1.0
1.2
Tra
nsm
itta
nce
CCD channel number
noise rmsequivalent to4.0x10 -9 cm -1
ICLAS water spectrum
1400 1500 1600 1700 1800 19000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Inte
nsi
ty (
A.U
.)
CCD channel number
Empty cell (3.5 torr)
4-step spectrum processing
• Frequency Linearization• Frequency calibration with reference
spectrum*• Baseline fluctuations correction & Peak
retrieval with a Gaussian fit• Intensity normalizations with reference
spectrum**Tolchenov, Tennyson et al 2002 & 2003
Absolute Intensity
RkNct g∫ =σαld
k: absolute line intensity (cm/molecule)N = 3.16x1016 x P (Torr) at 296 KR = 0.4 filling ratio of the absorption cell in the laser cavitytg = 150 µs
1x10 -27
1x10 -26
1x10 -25
H2
16O SP 2003 (calculated )
11420 11424 11428 11432
1x10 -27
1x10 -26
1x10 -25
Wavenumber (cm-1)
H2
16O ICLAS
1x10 -27
1x10 -26
1x10 -25
HITRAN 2004 (600 m. FTS - Reims) - H2
16O
H 216O FTS Tolchenov - JMS 2003
Inte
nsit
y (c
m/m
olec
ule)
11420 11424 11428 11432
1x10 -27
1x10 -26
1x10 -25
H216O
11400 11600 118001E-28
1E-27
1E-26
1E-25
1E-24
1E-23 Tolchenov et al JMS 2003 ICLAS Assigned
wavenumber (cm -1)
Inte
nsit
y (c
m/m
ol )
H2
16O
0.5
1.0
1E-26
1E-25
1E-24
11600 11605 116101E-27
1E-26
1E-25
1E-24
16
16
16 1
6
18 18
H2
18O-H2
16O ICLAS
H2
18OIn
tens
ity
(cm
/mo
lecu
le)
Inte
nsity
(c
m/m
ole
cule
) H
21 8O Kitt Peak
H2
1 6O FTS (RAL UCL)
Wavenumber (cm -1)
H2
18O SP 2000
Preliminary conclusions &Perspective
• Assign new lines of H216O and H2
18O spectranear 12000 cm-1
• H216O ICLAS: gain of a factor 5 in sensitivity
compared with FTS (Tolchenov)• H2
18O ICLAS: 1-2 orders of magnitude greatersensitivity
• Deuterated isotopologues of water: HDO andD2O
11000 11500 12000 12500 130001E-28
1E-27
1E-26
1E-25
1E-24
1E-23
1E-22
D2O SP2000
11000 11200 11400 11600 11800 12000 12200 12400 12600 128001E-28
1E-27
1E-26
1E-25
1E-24
1E-23
1E-22
Inte
nsi
ty (
cm/m
ole
cule
)
Wavenumber (cm -1)
HDO SP 2000
Ti:Sapphire(currently)
Campargue et al (JMS 2005)
1x10 -27
1x10 -26
H2
16O SP 2003 (calculated)
11496 11500 11504 11508 11512
1x10 -27
1x10 -26
Wavenumber (cm -1)
H216O ICLAS
1x10 -27
1x10 -26
HITRAN 2004 (FTS.) H2
16O
FTS Tolchenov 2003
11496 11500 11504 11508 115121x10 -26
H216O
1x10-26
H2
1 6O SP 2003 (calculated)
11548 11552 11556 11560 11564
1x10 -26
Wavenumber (cm -1)
H2
16O ICLAS
1x10 -26
HITRAN 2004 (FTS.) H2
16O
FTS Tolchenov 2003
11548 11552 11556 11560 115641x10 -26
H216O
1x10 -26
Wavenumber (cm-1)
H2
16O SP 2003 (calculated )
12788 12792 12796 12800 12804 12808 12812
1x10-26
H2
16O ICLAS
1x10 -26
HITRAN 2004 (FTS.) H2
16O
12788 12792 12796 12800 12804 12808 12812
1x10 -26
FTS Tolchenov 2002
H216O