Abstract
In wavelength modulation spectroscopy using diode lasers, detection limit of molecular absorption is often imposed by spurious fringe noises that arise from slight reflections among optical components. In an attempt to reduce this fringe effect, we propose and demonstrate the use of a one-dimensional focal plane array. With the help of a multiplexer, a single lock-in amplifier is employed to obtain multiple-channel signals from wavelength-modulated output of an array detector. It is found that the intensity change of the molecular absorption signal is nearly proportional to the transversal beam intensity distribution, whereas that of fringe noise is much less conspicuous. These features, as well as the phase difference among the channels, contribute to separate the signal and fringe noise components from the multiplexed spectra, leading to the overall improvement in the signal-to-noise ratio.
Similar content being viewed by others
References
H. Masusaki, T. Satoh, A. Ubukata, S.-Q. Wu, K. Matsumoto, H. Kuze and N. Takeuchi: J. Vac. Soc. Jpn. 42 (1999) 31.
S.-Q. Wu, H. Masusaki, T. Kimishima, H. Kuze and N. Takeuchi: Jpn. J. Appl. Phys. 38 (1999) 4788.
R. Okazawa, H. Kuze, H. Masusaki and N. Takeuchi: Jpn. J. Appl. Phys. 38 (1999) 4946.
S.-Q. Wu, T. Kimishima, H. Kuze and N. Takeuchi: Jpn. J. Appl. Phys. 39 (2000) 4034.
D. G. Lancaster, D. Richter and F. K. Tittel: Appl. Phys. B 69 (1999) 459.
G. Modugnoa, C. Corsia, M. Gabryscha and M. Inguscio: Opt. Commun. 145 (1998) 76.
R. Bhargava, D. C. Fernandez, M. D. Schaeberle and I. W. Levin: Appl. Spectrosc. 55 (2001) 1580.
Y. Yoshii, H. Kuze and N. Takeuchi: Jpn. J. Appl. Phys. 41 (2002) 5585.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wu, SQ., Kimishima, T., Yoshii, Y. et al. Reduction of Fringe Noise in Wavelength Modulation Spectroscopy Using a One-Dimensional Focal Plane Array. OPT REV 9, 189–192 (2002). https://doi.org/10.1007/s10043-002-0189-7
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s10043-002-0189-7