A simplified analytic model for gain saturation and power extraction in the flowing chemical oxygen-iodine laser

Hager, Gordon D.; Helms, Charles A.; Truesdell, Keith A.; Plummer, David N.; Erkkila, John H.; Crowell, Peter G.

doi:10.1109/3.535355

Cited by 47 publications

(19 citation statements)

References 5 publications

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“…For the study of unstable cavities, numerous models faithfully preserve the cavity geometry [8][9][10]. In cases of stable resonators, however, the Fabry-Perot cavity and the roof-top cavity are often used as the approximation model [3,[12][13][14]. The Fabry-Perot model was successful in estimating the output power and the chemical efficiency with respect to the outcoupling rate and the flow condition.…”

Section: Introductionmentioning

confidence: 99%

“…However, certain difficulty arises when using the Fabry-Perot model to predict the intensity pattern. The upstream-downstream optical coupling effect in COIL with stable cavity, known as the sugar scooping phenomenon, cannot be explained by the Fabry-Perot model [3,[13][14]. In order to simulate this phenomenon, Yang adopted the roof-top cavity model which forces the optical field to flip as it is reflected by one of the mirrors [14].…”

Section: Introductionmentioning

confidence: 99%

“…To get a better understanding of these processes and improve the laser design, reliable models have to be built. Early studies included only a 1D flowing process, a few chemical reactions that directly related to pumping and lasing, and simplified Fabry-Perot cavity [2,3]. Numerous improved models were developed in the following works.…”

Section: Introductionmentioning

confidence: 99%

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Coupled simulation of chemical lasers based on intracavity partially coherent light model and 3D CFD model

Wu¹,

Huai²,

Jia³

et al. 2011

Opt. Express

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Abstract:Coupled simulation based on intracavity partially coherent light model and 3D CFD model is firstly achieved in this paper. The dynamic equation of partially coherent intracavity field is derived based on partially coherent light theory. A numerical scheme for the coupled simulation as well as a method for computing the intracavity partially coherent field is given. The presented model explains the formation of the sugar scooping phenomenon, and enables studies on the dependence of the spatial mode spectrum on physical parameters of laser cavity and gain medium. Computational results show that as the flow rate of iodine increases, higher order mode components dominate in the partially coherent field. Results obtained by the proposed model are in good agreement with experimental results.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coupled simulation of chemical lasers based on intracavity partially coherent light model and 3D CFD model

Wu¹,

Huai²,

Jia³

et al. 2011

Opt. Express

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show abstract

“…The concentration of atomic iodine is about 3% of that of molecular oxygen and each iodine atom is repumped and cycled many times throughout the flow field during the lasing process. According to the assumptions made in 1) and 2), it can be obtained that n1+n2=n0, (1) n+n=[O2], (2) Proc. of SPIE Vol.…”

Section: Gain Saturation Equation Of the Sgk Model In Flowing Coilmentioning

confidence: 99%

<title>Effects of translational nonequilibrium on the performance of a flowing chemical oxygen-iodine laser</title>

Zhi¹,

Yan²,

Hu³

2003

SPIE Proceedings

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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 5torr, 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

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“…The dissociation of iodine has occurred upstream of the laser cavity and deactivation in the cavity during the lasing process is negligible. It means that nl+n2=n, (1) where n1 and n2 are the population of the excited state I(2P3/2) and the ground state I(2P]/2) (or the upper and lower laser level) of the atomic iodine, respectively, n is the total particle number of the atomic iodine entering the laser cavity. The concentration of 02 C ) is assumed to be negligible.…”

Section: Fundamental Expressions In Coilmentioning

confidence: 99%

<title>Modified simplified rate equation model of a flowing chemical oxygen-iodine laser and its application</title>

Yan¹,

Hu²,

Zhi³

2003

SPIE Proceedings

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A modified simplified rate equation (RE) model of flowing chemical oxygen-iodine laser (COIL), which is adapted to both the condition ofhomogeneous broadening and inhomogeneous broadening being ofimportance and the condition of inhomogeneous broadening being predominant, is presented for performance analyses of a COIL. By using the Voigt profile function and the gain-equal-loss approximation, a gain expression has been deduced from the rate equations of upper and lower level laser species. This gain expression is adapted to the conditions ofvery low gas pressure up to quite high pressure and can deal with the condition of lasing frequency being not equal to the central one of spectral profile.The expressions of output power and extraction efficiency in a flowing COIL can be obtained by solving the coupling equations of the deduced gain expression and the energy equation which expresses the complete transformation of the energy stored in singlet delta state oxygen into laser energy. By using these expressions, the RotoCOIL experiment is simulated, and obtained results agree well with experiment data. Effects of various adjustable parameters on the performances of COIL are also presented.

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A simplified analytic model for gain saturation and power extraction in the flowing chemical oxygen-iodine laser

Cited by 47 publications

References 5 publications

Coupled simulation of chemical lasers based on intracavity partially coherent light model and 3D CFD model

Coupled simulation of chemical lasers based on intracavity partially coherent light model and 3D CFD model

<title>Effects of translational nonequilibrium on the performance of a flowing chemical oxygen-iodine laser</title>

<title>Modified simplified rate equation model of a flowing chemical oxygen-iodine laser and its application</title>

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