Abstract
We discuss experimental and theoretical results of absorption features of the oxygen A-band transitions in the optically thick regime when synchronous detection at higher harmonics (N≥2), using wavelength modulation spectroscopy (WMS), is performed. We show that the absorption saturation effects demonstrate a distinctive feature which results in suppression of the line-center lobes of the harmonic signals. These effects depend on the optical pathlength as well as on the modulation index. The rich structure of WMS signals, especially at higher detection orders, is central to the technique’s advantages in resolving spectra congested with highly disparate oscillator-strength lines. The effect of pathlength saturation on this structure is investigated.
Similar content being viewed by others
References
A.N. Dharamsi, J. Phys. D: Appl. Phys. 29, 540 (1996)
A.N. Dharamsi, Y. Lu, Appl. Phys. B 62, 273 (1996)
A.N. Dharamsi, A.M. Bullock, Appl. Phys. B 63, 283 (1996)
M. Amir Khan, K.D. Mohan, A.N. Dharamsi, in IEEE Lasers and Electro-Optics Society, 21st Annual Meeting, pp. 9–13, 648–649 (2008)
M. Amir Khan, K.D. Mohan, A.N. Dharamsi, Proc. SPIE 7229, 72290P (2009)
L.H. Aller, Atoms, Stars, and Nebulae, 3rd edn. (Cambridge University Press, Cambridge, 1991)
M. Khan, K.D. Mohan, A.N. Dharamsi, in Proceedings, Vol. 6378, Chemical and Biological Sensors for Industrial and Environmental Monitoring II, SPIE Symposium on Optics East, pp. 1–4, 6378–47, October (2006)
G.V.H. Wilson, J. Appl. Phys. 34, 3276 (1963)
A.M. Bullock, A.N. Dharamsi, J. Appl. Phys. 84, 6929 (1998)
J. Altman, R. Baumgart, C. Weitkamp, Appl. Opt. 20, 995 (1981)
A. Rothman, A. Barbe, D.C. Benner, L.R. Brown, C. Camy-Peyret, M.R. Carleer, K. Chance, C. Clerbaux, V. Dana, V.M. Devi, A. Fayt, J.-M. Flaud, R.R. Gamache, A. Goldman, D. Jacquemart, K.W. Jucks, W.J. Lafferty, J.-Y. Mandin, S.T. Massie, V. Nemtchinov, D.A. Newnham, A. Perrin, C.P. Rinsland, J. Schroeder, K.M. Smith, M.A.H. Smith, K. Tang, R.A. Toth, J. Vander Auwera, P. Varanasi, K. Yoshino, J. Quant. Spectrosc. Radiat. Transfer 82, 5 (2003). The 2008 HITRAN Database lists a value of 13151.34866 cm−1 for the RR (13, 13) line. The results obtained in this paper (using the value of 13151.34015 cm−1) are not affected since the wavelength scales in the figures are with respect to the center of this line itself
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Amir Khan, M., Mohan, K. & Dharamsi, A.N. Optical pathlength saturation signatures in wavelength modulation spectroscopy signals of atmospheric molecular oxygen. Appl. Phys. B 99, 363–369 (2010). https://doi.org/10.1007/s00340-009-3814-3
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00340-009-3814-3