Abstract

When used for trace-gas detection, laser absorption spectroscopy is usually limited by false absorption signals that are traceable to interferometric effects induced by windows and other pairs of optical surfaces. Here we introduce a new technique that can selectively reject these étalon fringes while preserving the true absorption signal over a wide range of étalon free spectral range to absorption linewidth ratios. We present a theoretical analysis and experimental verification by using a tunable lead salt diode laser.

© 1992 Optical Society of America

Frequency modulation and wavelength modulation spectroscopies: comparison of experimental methods using a lead-salt diode laser

David S. Bomse, Alan C. Stanton, and Joel A. Silver
Appl. Opt. 31(6) 718-731 (1992)

Fringe pattern suppression in intracavity laser spectroscopy

P. Vujkovic Cvijin, W. K. Wells, D. A. Gilmore, J. Wu, D. M. Hunten, and G. H. Atkinson
Appl. Opt. 31(27) 5779-5784 (1992)

Optical fringe reduction technique for FM laser spectroscopy

Nee-Yin Chou, Glen W. Sachse, Liang-Guo Wang, and Thomas F. Gallagher
Appl. Opt. 28(23) 4973-4975 (1989)

Combined wavelength and frequency modulation spectroscopy: a novel diagnostic tool for materials processing

H. C. Sun, E. A. Whittaker, Y. W. Bae, C. K. Ng, V. Patel, W. H. Tam, S. McGuire, B. Singh, and B. Gallois
Appl. Opt. 32(6) 885-893 (1993)

Frequency-modulation spectroscopy for trace species detection: theory and comparison among experimental methods

Joel A. Silver
Appl. Opt. 31(6) 707-717 (1992)