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DIODE- AND DIFFERENCE-FREQUENCY LASER STUDIES OF ATMOSPHERIC MOLECULES IN THE NEAR- AND MID-INFRARED: H 2 O, NH 3, and NO 2 Johannes ORPHAL, Pascale CHELIN,

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Presentation on theme: "DIODE- AND DIFFERENCE-FREQUENCY LASER STUDIES OF ATMOSPHERIC MOLECULES IN THE NEAR- AND MID-INFRARED: H 2 O, NH 3, and NO 2 Johannes ORPHAL, Pascale CHELIN,"— Presentation transcript:

1 DIODE- AND DIFFERENCE-FREQUENCY LASER STUDIES OF ATMOSPHERIC MOLECULES IN THE NEAR- AND MID-INFRARED: H 2 O, NH 3, and NO 2 Johannes ORPHAL, Pascale CHELIN, Nofal IBRAHIM, and Pierre-Marie FLAUD Laboratoire Interuniversitaire des Systèmes Atmosphériques Université de Paris-12, Créteil, France

2 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 2 Tunable diode-lasers are available in the near-infrared region: 0.7 – 2.0 m (optical telecommunication) Extremely useful for quantitative spectroscopy of atmospheric molecules (many studies in the last 5 years) Very high-resolution (less than 0.0001 cm -1 ) with external cavities Many photons (at least a few mW) on output High signal/noise ratio (a few 1000) in short measurement time Single wavelength, tunable over several 10 nms (a few 100 cm -1 ) A laser based on difference-frequency generation can transport these properties into the mid-infrared (3 – 5 m) This talk: applications to H 2 O, NH 3, NO 2 This talk: applications to H 2 O, NH 3, NO 2 Quantitative Spectroscopy Using IR Lasers Quantitative Spectroscopy Using IR Lasers

3 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 3 Toptica DL-100 (Littrow configuration) External Cavity Diode-Lasers External Cavity Diode-Lasers grating forms part of the cavity linewidth 1 MHz (0.00003 cm -1 ) output power up to 30 mW spectral range: 810 – 880 nm (11360 – 12350 cm -1 ) 1535 – 1565 nm (6390 – 6515 cm -1 ) tunable range (single mode) at least 20-30 GHz (0.6-1.0 cm -1 ) relatively small beam divergence

4 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 4 H 2 O absorption line around 830 nm External Cavity Diode-Lasers External Cavity Diode-Lasers

5 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 5 White-type absorption cell L = 1 m, maximum path length 100 m, CaF 2 windows 3 MKS Baratrons Water sample Thermometer

6 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 6 The H 2 O band around 822 nm

7 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 7 R. A. Toth, J. Mol. Spectrosc., 166, 176-183 (1994) J.-M. Flaud et al., J. Mol. Spectrosc., 185, 211-221 (1997) P. L. Ponsardin et al., J. Mol. Spectrosc., 185, 58-70 (1997) A. Lucchesini et al., Eur. Phys. J. D., 8, 223-226 (2000) R. Schermaul et al, J. Mol. Spectrosc. 208, 32-42 (2001) A. Ray et al., Appl. Phys. B, 79, 915-921(2004) Previous measurements of H 2 O around 822 nm Example: line intensities ( S 10 23 /cm molecule -1 ) position (cm -1 )HITRAN04PonsardinSchermaulRay 12014.14311.679---1.9601.504 12218.82481.8652.1852.2901.888 12244.72333.2363.815.080--- 12244.78730.8881.08--- ! Differences between different authors exceed stated accuracy (up to 30%) need for more measurements

8 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 8 Experimental Precautions H 2 O samples: distilled, cleaned by ultrasonic procedure Calibrating the MKS Baratron heads Validation of detector linearity using neutral density filters Linearization of the wavenumber axis: FP etalon (1 MHz) Simultaneous recording of HDO lines (in the mid-IR using a DFG laser) to validate H 2 O pressure values (assumption: natural HDO abundance); result: less than 2 % deviations Background emission of the ECDL narrow spectral filter Validate analysis software with synthetic lines

9 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 9 10 Results from LISA Example 1: Self-broadening of the line at 12226.101 cm -1 High S/N ratio( >1000) Experimental lines well reproduced using Voigt profile Weak residuals due to Dicke narrowing

10 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 10 Results from LISA Example 2: Air-broadening of the line at 12226.101 cm -1 Again: weak residuals due to Dicke narrowing (even at 200 Torr)

11 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 11 Results from LISA Example 3: Self-broadening of 3 lines near 12259 cm -1 Note: the Dicke-narrowing also affects the baseline between the lines

12 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 12 Line intensities Note: Straight lines (1-2 %) Up to 10 % difference between fixed and free D in the Voigt profile MEAN value (!) 15 % above HITRAN2004 Good agreement (5 %) with Ponsardin and Browell, JMS 1997 Difference can not be explained by line profile Fixed Free

13 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 13 Self-broadeningSelf-broadening Note: Straight line (1 %) BUT: 10 % lower than HITRAN2004

14 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 14 Air-broadeningAir-broadening Note: Straight line (< 1 %) Good agreement with HITRAN2004 (< 5 %)

15 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 15 Conclusions for H 2 O around 822 nm 40 different H 2 O lines measured between 815 and 835 nm. Intensities in the 830 nm band 15% higher than HITRAN2004. Self-broadening coefficients 10% lower than HITRAN2004. Air-broadening coefficients in good agreement (< 5%) with HITRAN2004. Dicke-narrowing although weak, check impact on line intensities using other profiles (Galatry, Rautian,…) Perform new, independent experiments (FTS?) Strategies for H 2 O broadening in HITRAN

16 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 16 Toptica DL-100 (Littrow configuration) External Cavity Diode-Lasers External Cavity Diode-Lasers grating as part of the cavity linewidth 1 MHz (0.00003 cm -1 ) output power up to 30 mW spectral range: 810 – 880 nm (11360 – 12350 cm -1 ) 1535 – 1565 nm (6390 – 6515 cm -1 ) tunable range (single mode) at least 20-30 GHz (0.6-1.0 cm -1 ) relatively low beam divergence

17 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 17 Toptica DL-100 (Littrow configuration) External Cavity Diode-Lasers External Cavity Diode-Lasers output power up to 30 mW Photo-acoustic spectroscopy (PAS)

18 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 18 Reminder: How works PAS Thanks to Prof. Th. Huet, University of Lille, France Photoacoustic effect: Collisional energy transfer Laser tuned to a molecular transition: Excited molecules Partly, non radiative de-excitation Temperature changes Pressure changes Acoustic wave Detection by microphone Photoacoustic Spectroscopy of NH 3 around 1.5 m Photoacoustic Spectroscopy of NH 3 around 1.5 m

19 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 19 Simultaneous direct absorption measurements using a White-type multiple-pass cell Photoacoustic Spectroscopy of NH 3 around 1.5 m Photoacoustic Spectroscopy of NH 3 around 1.5 m

20 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 20 Simultaneous direct absorption measurements using a White-type multiple-pass cell Photoacoustic Spectroscopy of NH 3 around 1.5 m Photoacoustic Spectroscopy of NH 3 around 1.5 m

21 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 21 Photoacoustic Spectroscopy of NH 3 around 1.5 m Photoacoustic Spectroscopy of NH 3 around 1.5 m Spectral calibration using the FTS line positions of Lundsberg-Nielsen et al. (1993)

22 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 22 Problem: The relative line intensities seem to be incorrect: Lines No. 2 and 3 should be very similar, about 60 % of the line No. 1 Check with direct absorption spectra Photoacoustic Spectroscopy of NH 3 around 1.5 m Photoacoustic Spectroscopy of NH 3 around 1.5 m 1 2 3

23 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 23 1 2 3 Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m Spectral calibration using the FTS line positions of Lundsberg-Nielsen et al. (1993)

24 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 24 Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m

25 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 25 Problem: The relative line intensities seem to be incorrect: Lines No. 2 and 3 should be very similar, about 60 % of the line No. 1 The fitted Doppler widths are not equal ! Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m Spectral calibration using the FTS line positions of Lundsberg-Nielsen et al. (1993)

26 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 26 New absorption spectra using FTS: Bruker IFS 120 HR Fourier spectrometer (Orsay) Absorption cell 25 cm, CaF 2 windows NH 3 pressure 30 mbar Spectral range 5950 – 7850 cm -1 Spectral resolution 0.02 cm -1 Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m

27 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 27 14 NH 3 15 NH 3 Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m

28 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 28 14 NH 3 15 NH 3 Line No. Lundsberg-Nielsen et al. JMS 162 (1993) This work (FTS) (*) Difference in cm -1 16528.7646528.75850.0055 26528.8946528.88280.0112 36529.1846529.17660.0074 (*) calibrated using the IUPAC recommended standard: H 2 O lines of Toth, accuracy (RMS) 0.0005 cm -1 The new NH 3 linelist is available in digital format upon request to the authors. Absorption Spectroscopy of NH 3 around 1.5 m Absorption Spectroscopy of NH 3 around 1.5 m Comparison of the NH 3 line positions (example)

29 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 29 Chopper Wavemeter DFG DFG (Difference Frequency Generation) Laser) Mid-IR NO 2 line intensities using a DFG laser Mid IR ECDL: 30 mW 810 - 880 nm Linewidth 1 MHz DFG 3 - 5 µm Linewidth 1MHz Lock-in detection LabView acquisition S/N>1000 Measurement time: few minutes

30 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 30 ECDL: 30 mW 810 - 880 nm Linewidth 1 MHz DFG 3 - 5 µm Linewidth 1MHz Lock-in detection LabView acquisition S/N>1000 Measurement time: few minutes DFG DFG (Difference Frequency Generation) Laser) Mid-IR NO 2 line intensities using a DFG laser

31 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 31 ECDL: 30 mW 810 - 880 nm Linewidth 1 MHz DFG 3 - 5 µm Linewidth 1MHz Lock-in detection LabView acquisition S/N>1000 Measurement time: few minutes DFG DFG (Difference Frequency Generation) Laser) Mid-IR NO 2 line intensities using a DFG laser

32 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 32 P N2O = 0.075 mbar II.1. Caractérisation instrumentale: spectroscopie de N 2 O. Interféromètre de Fabry Pérot, Validation avec N 2 O. Validation of the DFG using N 2 O, CH 4 and HI Validation of the DFG using N 2 O, CH 4 and HI Mid-IR NO 2 line intensities using a DFG laser

33 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 33 P N2O = 7,5.10 -2 mbar II.1. Caractérisation instrumentale: spectroscopie de N 2 O. Interféromètre de Fabry Pérot, Validation avec N 2 O. Validation of the DFG using N 2 O, CH 4 and HI Validation of the DFG using N 2 O, CH 4 and HI Mid-IR NO 2 line intensities using a DFG laser RMS deviation 0.00006 cm -1

34 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 34 II.1. Caractérisation instrumentale: spectroscopie de N 2 O. Interféromètre de Fabry Pérot, Validation avec N 2 O. Validation of the DFG using N 2 O, CH 4 and HI Validation of the DFG using N 2 O, CH 4 and HI Mid-IR NO 2 line intensities using a DFG laser RMS deviation 0.7 %

35 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 35 Spectre dabsorption de la bande fondamentale de HI. Bande dabsorption υ 1 Validation of the DFG using N 2 O, CH 4 and HI Validation of the DFG using N 2 O, CH 4 and HI Mid-IR NO 2 line intensities using a DFG laser R(0)

36 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 36 Spectre dabsorption de la bande fondamentale de HI. Bande dabsorption υ 1 Validation of the DFG using N 2 O, CH 4 and HI Validation of the DFG using N 2 O, CH 4 and HI Mid-IR NO 2 line intensities using a DFG laser

37 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 37 II.2. Intensités de raies de NO 2. Motivations NO 2 concentrations determined using the VIS NO 2 concentrations determined using the VIS Mid-IR NO 2 line intensities using a DFG laser

38 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 38 II.2. Intensités de raies de NO 2. Motivations NO 2 concentrations determined using the VIS NO 2 concentrations determined using the VIS Mid-IR NO 2 line intensities using a DFG laser

39 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 39 II.2. Intensités de raies de NO 2. Motivations NO 2 concentrations determined using the VIS NO 2 concentrations determined using the VIS Mid-IR NO 2 line intensities using a DFG laser

40 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 40 II.2. Intensités de raies de NO 2. Motivations Typical mid-IR spectrum and fit (residuals × 25) Typical mid-IR spectrum and fit (residuals × 25) Mid-IR NO 2 line intensities using a DFG laser résidu x 25 υ 1 + υ 3 (υ 1 + υ 2 + υ 3 )- υ 2 P NO2 = 2 mbar

41 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 41 II.2. Intensités de raies de NO 2. Motivations Mid-IR NO 2 line intensities using a DFG laser

42 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 42 II.2. Intensités de raies de NO 2. Motivations Results for the cold band 1 + 3 Results for the cold band 1 + 3 27 lines measured 27 lines measured Mean deviation wrt. HITRAN2004: - 4.9 % ± 1.2 % Mean deviation wrt. HITRAN2004: - 4.9 % ± 1.2 % Results for the hot band ( 1 + 2 + 3 ) - 2 Results for the hot band ( 1 + 2 + 3 ) - 2 8 lines measured (many lines are blended) 8 lines measured (many lines are blended) Mean deviation wrt. HITRAN2004: - 2.3 % ± 1.2 % Mean deviation wrt. HITRAN2004: - 2.3 % ± 1.2 % Line positions of the hot band ( 1 + 2 + 3 ) - 2 slightly shifted (see also Perrin et al., 1997) Line positions of the hot band ( 1 + 2 + 3 ) - 2 slightly shifted (see also Perrin et al., 1997) Mid-IR NO 2 line intensities using a DFG laser

43 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 43 Using ECDL for studying line intensities and shapes in the near- and mid-IR, at very high S/N and spectral resolution DFG lasers can transport these properties into the mid- infrared (3 – 5 m) and possibly at longer wavelengths H 2 O: line intensities of the 822 nm band 15 % too low H 2 O: line intensities of the 822 nm band 15 % too low NH 3 : new NIR line list recorded using FTS NH 3 : new NIR line list recorded using FTS NO 2 : very good agreement between UV and IR at 3 m NO 2 : very good agreement between UV and IR at 3 m Further studies: H 2 CO, O 3, HO 2 … Further studies: H 2 CO, O 3, HO 2 … Conclusions Conclusions

44 Quantitative Spectroscopy Using Diode- and DFG Lasers in the IR 9th International HITRAN Conference, Cambridge, June 26, 2006 44 Pierre-Marie Flaud (PhD, 2003-2005) Nofal Ibrahim (PhD, 2003-2006) Acknowledgements Acknowledgements CNRS Department Sciences Physique et Mathématiques University of Paris-12 Créteil


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