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Proceedings Paper

Effects of translational nonequilibrium on the performance of a flowing chemical oxygen-iodine laser
Author(s): Zhi Gao; Hai-Xing Yan; Li-Min Hu
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Paper Abstract

The effect of the translational nonequilibrium on performance modeling of flowing chemical oxygen-iodine lasers (COIL) is emphasized in this paper. The spectral line broadening (SLB) model is a basic factor for predicting the performances of flowing COIL. The Voigt profile function is a well-known SLB model and is usually utilized. In the case of gas pressure in laser cavity less than 5 torr, a low pressure limit expression of the Voigt profile function is used. These two SLB models imply that all lasing particles can interact with monochromatic laser radiation. Basically, the inhomogeneous broadening effects are not considered in these two SLB models and they cannot predict the spectral content. The latter requires consideration of finite translational relaxation rate. Unfortunately, it is rather difficult to solve simultaneously the Navier-Stokes (NS) equations and the conservation equations of the number of lasing particles per unit volume and per unit frequency interval. In the operating condition of flowing COIL, it is possible to obtain a perturbational solution of the conservational equations for lasing particles and deduce a new relation between the gain and the optical intensity, i.e., a new gain-saturation relation. By coupling the gain-saturation relation with other governing equations (such as the NS equations, chemical reaction equations and the optical model of gain-equal-loss), we have numerically calculated the performances of flowing COIL. The present results are compared with those obtained by the common rate-equation (RE) model, in which the Voigt profile function and its low pressure limit expression are used. The difference of different model’s results is great. For instance, in the case of lasing frequency coinciding with the central frequency of line profile and very low gas pressure, the gain saturation relation of the present model is quite different with that of the RE model.

Paper Details

Date Published: 10 November 2003
PDF: 11 pages
Proc. SPIE 5120, XIV International Symposium on Gas Flow, Chemical Lasers, and High-Power Lasers, (10 November 2003); doi: 10.1117/12.515646
Show Author Affiliations
Zhi Gao, Institute of Mechanics (China)
Hai-Xing Yan, Institute of Mechanics (China)
Li-Min Hu, Institute of Mechanics (China)

Published in SPIE Proceedings Vol. 5120:
XIV International Symposium on Gas Flow, Chemical Lasers, and High-Power Lasers
Krzysztof M. Abramski; Edward F. Plinski; Wieslaw Wolinski, Editor(s)

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