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