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Quantum-limited FM-spectroscopy with a lead-salt diode laser

A comparison of theoretical and experimental data

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Abstract

Ultrasensitive absorption spectroscopy of NO2 was performed with a tunable lead-salt diode laser (TDL) using a single-tone high-frequency modulation (FM) technique. With a detection bandwidth of 200 kHz, an optical density of 2.7 × 10−5 was detectable at SNR of 1. The detectable optical density could be further improved by reducing the detection bandwidth in agreement with the √Δf relationship, reaching 2.5 × 10−6 at a detection bandwidth of 1.56 kHz. Normalized to 1 Hz bandwidth, the demonstrated performance would then correspond to a detectable optical density of 5.9 × 10−8. This detection limit agrees well with the calculated “quantum limited” performance based on the measured laser power, modulation index, noise figure of the electronic components, and other parameters of the apparatus. These measurements and calculations show that by implementation of the FM technique, the sensitivity of the present TDL absorption spectrometers (TDLAS) can be improved by at least a factor of 10 and possibly even of 100. Such a sensitivity improvement would greatly extend the applicability of TDLAS for trace gas analysis, especially in atmospheric monitoring.

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References

  1. D.R. Hastie, G.I. Mackay, T. Iguchi, B.A. Ridley, H.I. Schiff: Environ. Sci. Technol. 17, 352A (1983)

  2. R. Grisar, H. Preier, G. Schmidtke, G. Restelli (eds.): Monitoring of Gaseous Pollutants by Tunable Diode Lasers (Reidel, Dordrecht 1987)

    Google Scholar 

  3. C.R. Webster, R.T. Menzies, E.D. Hinkley: In Laser Remote Chemical Analysis ed. by R.M. Measures (Wiley, New York 1988) p. 163

    Google Scholar 

  4. D.T. Cassidy, J. Reid: Appl. Opt. 21, 2527 (1982)

    Google Scholar 

  5. J.A. Silver, A.C. Stanton: Appl. Opt. 26, 2558 (1987)

    Google Scholar 

  6. G.W. Sachse, G.F. Hill, L.O. Wade, M.G. Perry: J. Geophys. Res. 92, 2071 (1987)

    Google Scholar 

  7. A. Fried, R. Sams, W.W. Berg: Tunable Diode Laser Development and Spectroscopy Applications (Proceedings of SPIE, Volume 438, W. Lo editor, Washington 1983)

  8. J. Reid, M. El-Sherbiny, B.K. Garside, E.A. Ballik: Appl. Opt. 19, 3349 (1980)

    Google Scholar 

  9. P. Werle, F. Slemr, M. Gehrtz, C. Bräuchle: Appl. Opt. (1989) (in press)

  10. J.L. Hall, T. Baer, L. Hallberg, H.G. Robinson: In Laser Spectroscopy V, ed. by A.R.W. McKellar, T. Oka, B.P. Stoicheff, Springer Ser. Opt. Sci. Vol. 30 (Springer, Berlin, Heidelberg 1981) p. 16

    Google Scholar 

  11. G.C. Bjorklund: Opt. Lett. 5, 15 (1980)

    Google Scholar 

  12. W. Lenth: Opt. Lett. 8, 575 (1983)

    Google Scholar 

  13. W. Lenth: IEEE J. QE-20, 1045 (1984)

    Google Scholar 

  14. M. Gehrtz, W. Lenth, A.T. Young, H.S. Johnston: Opt. Lett. 11, 132 (1986)

    Google Scholar 

  15. G.C. Bjorklund, M.D. Levenson, W. Lenth, C. Ortiz: Appl. Phys. B 32, 154 (1983)

    Google Scholar 

  16. M. Osinsky, J. Buus: IEEE J. QE-23, 9 (1987)

    Google Scholar 

  17. D.E. Cooper, R.E. Warren: Appl. Opt. 26, 3726 (1987)

    Google Scholar 

  18. S. Kobayashi, Y. Yamamoto, M. Ito, T. Kimura: IEEE J. QE-18, 582 (1982)

    Google Scholar 

  19. W. Lenth, M. Gehrtz: Appl. Phys. Lett. 47, 1263 (1985)

    Google Scholar 

  20. J.A. Silver, A.C. Stanton: Appl. Opt. 27, 4438 (1988)

    Google Scholar 

  21. N.-Y. Chou, G.W. Sachse: Appl. Opt. 26, 3584 (1987)

    Google Scholar 

  22. D.E. Cooper, C.B. Carlisle: Opt. Lett. 13, 719 (1988)

    Google Scholar 

  23. C.R. Webster: J. Opt. Soc. Am. B 2, 1464 (1985)

    Google Scholar 

  24. B.B. Hicks, M.L. Wesely, J.L. Durham: Critique of methods to measure dry deposition: Workshop summary EPA-600/9-80-050, Washington DC, EPA, 83, 1980

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Werle, P., Slemr, F., Gehrtz, M. et al. Quantum-limited FM-spectroscopy with a lead-salt diode laser. Appl. Phys. B 49, 99–108 (1989). https://doi.org/10.1007/BF00332268

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