broadband mid-infrared comb-resolved fourier transform spectroscopy kevin f. lee a. mills, c. mohr,...
TRANSCRIPT
![Page 1: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/1.jpg)
Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy
Kevin F. LeeA. Mills, C. Mohr, Jie Jiang,
Martin E. FermannP. Masłowski
![Page 2: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/2.jpg)
Spectroscopy
absorption spectra of gases
midinfrared• strong fundamental
vibrations
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New system
midinfrared comb & FTIR
• bright• 30 mW• coherent
• broadband• parallel
– fast
• comb resolution• 200 kHz linewidth
– optically referenced• referenced to GPS
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Comparison
other methods
• single-frequency laser• bright• precise• narrowband• slow scan
• LED, glowbar• broadband• incoherent• low resolution
• VIPA spectrometer• comb-resolved• narrowband ~10 nm
midinfrared comb & FTIR
• bright• 30 mW• coherent
• broadband• parallel
– fast
• comb resolution• 200 kHz linewidth
– optically referenced• referenced to GPS
![Page 5: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/5.jpg)
Absorption Lines
measure line parameters
need resolution
• linewidths• Doppler broadened to ~ 100 MHz
• want resolution ~ 10 MHz~ 0.0003 cm-1
need speed
• multiple lines• temperatures• pressures
11 Torr
150 Torr
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Frequency combs
stable train of laser pulses
• stable frequency comb
active coherent lock
• first tooth • carrier envelope offset
(CEO)
• optical tooth to a reference
• whole comb stable
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Midinfrared comb
OPO comb
• inherits repetition rate
• same optical reference
scan comb lines by tuning reference wavelength
• access any frequency
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Sample
100 m path length multipass cell
• uses coherence & power
• increases absorption
parts-per-billion sensitivity
• minimum detectable absorption
• 10-6 cm-1Hz-1/2
• low pressures and concentrations
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Spectrometer
Fourier transform spectrometer (FTIR)
• record intensity vs. path delay
• time domain data• FT to get spectrum
• broadband
for 10 MHz resolution
• 30 m optical path delay
• too long, use comb
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Comb-resolved FTIR
match FTIR to comb
• alternating pixels with and without comb lines
• spectrum with 200 kHz linewidth elements
our FTIR• 16 cm stage• 8 pass• 234 MHz• 2'x2' breadboard
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Absolute frequency
comb frequencies from measured repetition rate
• GPS referenced
FTIR self-calibrated
150 MHz mismatch with HITRAN
1 / frep
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Measure CO in Ar
50+ CO absorption lines
scan comb by ~30 MHz steps
• 13 comb-resolved spectra
• 1 000 000+ comb teeth
CO fundamental
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Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 14: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/14.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 15: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/15.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 16: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/16.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 17: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/17.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 18: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/18.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 19: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/19.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 20: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/20.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 21: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/21.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 22: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/22.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 23: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/23.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 24: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/24.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 25: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/25.jpg)
Comb Scan of CO
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
![Page 26: Broadband Mid-infrared Comb-Resolved Fourier Transform Spectroscopy Kevin F. Lee A. Mills, C. Mohr, Jie Jiang, Martin E. Fermann P. Masłowski](https://reader035.vdocument.in/reader035/viewer/2022070410/56649f285503460f94c4096d/html5/thumbnails/26.jpg)
Comb Scan of CO
170 MHz
30 MHz spacing(chosen)
234 MHz FTIR resolution
11 TorrCO in Ar2 ppm
line P62119.7 cm-1
150 kHz linewidth
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Lineshape analysis
simple Voigt profile at high pressure
see speed dependence at low pressure
Voigt profile
speed dependentVoigt profile
Residuals
404 Torr 27 Torr
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Pressure dependence
fit with 4 pressures
• compare to Wehr et al. 2006
• shifting– 17% match
• broadening – 4% match
50 lines * 4 pressures
• 1 hour by comb
• 1 month by cw-CRDSCO fundamental P7
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Summary
OPO comb & FTIR
broadband midIR
comb-resolved