Abstract
Tunable Diode-Laser Absorption Spectroscopy (TDLAS) is increasingly being used to measure trace-gas concentrations down to low part-per-billion levels (1 ppbv = 10−9 volume mixing ratio). Semiconductor lead-salt diode lasers give access to the mid-infrared spectral region and the application of high-Frequency Modulation (FM) schemes can further improve the sensitivity and detection speed of modern instrumentation. Several factors influence or even limit spectrometer performance. The central elements in such spectrometers are lead-salt diode lasers. Experimental data will be presented, which demonstrate that high-frequency excess-noise contributions above several MHz can be attributed to mode hopping and mode partition noise during multimode laser operation. Additionally it will be discussed how a FM-TDLAS spectrometer can be interpreted as an optimized Michelson interferometer for absolute distance measurements and, therefore, is extremely sensitive towards drift effects. The higher the modulation frequency, the higher is the drift sensitivity of the spectrometer due to interferometric effects. These drift effects are a second factor affecting ultrasensitive measurements. While wideband-laser noise characteristics call for high modulation frequencies, the aforementioned interferometric effects in the spectrometer require low modulation frequencies.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
B.J. Finlayson-Pitts, J.N. Pitts:Atmospheric Chemistry (Wiley, New York 1986) p. 326
H.I. Schiff, U. Platt (eds.):Optical Methods in Atmospheric Chemistry, SPIE Proc.1715 (1993)
C.R. Webster, R.T. Menzies, E.D. Hinkley: InLaser Remote Chemical Analysis, ed. by R.M. Measures (Wiley, New York 1988) p. 163
R. Grisar, H. Böttner, M. Tacke, G. Restelli (eds.):Monitoring of Gaseous Pollutants by Tunable Diode Lasers (Kluwer, Dordrecht 1992)
W.F. Dabberdt, D.H. Lenschow, T.W. Horst, P.R. Zimmerman, S.P. Oncley, A.C. Delany: Science260, 1472 (1993)
P. Werle, R. Mücke, F. Slemr: Appl. Phys. B57, 131 (1993)
G.C. Bjorklund, M.D. Levenson, W. Lenth, C. Ortiz: Appl. Phys. B32, 145 (1983)
M. Gehrtz, W. Lenth, A.T. Young, H.S. Johnston: Opt. Lett.11, 132 (1986)
D.E. Cooper, J.P. Watjen: Opt. Lett.11, 606 (1986)
P. Werle, F. Slemr, M. Gehrtz, Chr. Bräuchle: Appl. Phys. B49, 99 (1989)
P. Werle: InSubstance Detection Systems, ed. by G. Harding, R.C. Lanza, L.J. Myers, P.A. Young, SPIE Proc.2092, 4 (1994).
P. Werle, B. Scheumann, J. Schandl: Opt. Eng.33, 9 (1994)
M. Osinsky, J. Buus: IEEE J. QE-23, 9 (1987)
P. Werle, F. Slemr, M. Gehrtz, Chr. Bräuchle: Appl. Opt.28, 1638 (1989)
P. Werle, F. Slemr: Appl. Opt.30, 430 (1991)
K. Petermann:Laser Diode Modulation and Noise (Kluwer, Dordrecht 1991)
J.L. Hall, T. Baer, L. Hallberg, H.G. Robinson: InLaser Spectroscopy V, ed by. A.R.W. McKellar, T. Oka, B.P. Stoicheff, Springer Ser. Opt. Sci., Vol. 39 (Springer, Berlin, Heidelberg 1981) p. 16
R.S. Eng, A.W. Mantz, T.R. Todd: Appl. Opt.18, 1088 (1979)
H. Fischer, M. Tacke: J. Opt. Soc. Am. B8, 1824 (1991)
D.E. Cooper, T.F. Gallagher: Appl. Opt.24, 1327 (1984)
J.A. Silver: Appl. Opt.31, 707 (1992)
D.S. Bomse, A.C. Stanton, J.A. Silver: Appl. Opt.31, 718 (1992)
D.E. Cooper, C.B. Carlisle: InMonitoring of Gaseous Pollutants by Tunable Diode Lasers, ed. by R. Grisar, G. Schmidtke, M. Tacke, G. Restelli (Kluwer, Dordrecht 1989)
D.E. Cooper, R.E. Warren: Appl. Opt.26, 3726 (1987)
N.-Y. Chou, G.W. Sachse: Appl. Opt.26, 3584 (1987)
K.Y. Lau, Ch. Harder, A. Yariv: Appl. Phys. Lett.44, 273 (1984)
R. Dändliker, R. Thalmann, D. Prongué: Opt. Lett.13, 339 (1988)
O. Sasaki, H. Sasazaki, T. Suzuki: Appl. Opt.30, 4040 (1991)
P. de Groot, S. Kishner: Appl. Opt.30, 4026 (1991)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Werle, P. Laser excess noise and interferometric effects in frequency-modulated diode-laser spectrometers. Appl. Phys. B 60, 499–506 (1995). https://doi.org/10.1007/BF01080927
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01080927