A three-level model for alkali metal vapor lasers. Part II: broadband optical pumping

Hager, Gordon D.; Perram, Glen P.

doi:10.1007/s00340-013-5371-z

Cited by 37 publications

(10 citation statements)

References 24 publications

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“…is the pump normalized Gaussian spectral distribution of full width at half-maximum (FWHM) Δν p [16]. The laser intensities in both directions I l z are assumed to be monochromatic and their spatial variations are described by equations similar to (11):…”

Section: F Spatial Variations Of the Pump And Laser Radiationmentioning

confidence: 99%

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Computational fluid dynamics modeling of subsonic flowing-gas diode-pumped alkali lasers: comparison with semi-analytical model calculations and with experimental results

2014

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Comprehensive analysis of kinetic and fluid dynamic processes in flowing-gas diode-pumped alkali lasers (DPALs) using two-and three-dimensional computational fluid dynamics (2D and 3D CFD) models is reported. The 2D model is applied to a Cs DPAL with optical resonator-flow field coaxial configuration and the 3D model is applied to an optical axis transverse to the flow configuration. The models take into account effects of temperature rise and losses of Cs atoms due to ionization. The 2D CFD model is applied to 1 kW flowing-gas Cs DPAL [Quantum Electron. 42, 95 (2012)] and the calculated results are in good agreement with the measurements. Comparison of the 2D CFD to semi-analytical model [J. Opt. Soc. Am. B 30, 1118] shows that for low pump power both models predict very close values of the laser power; however, at higher pump power, corresponding to saturation of the absorption of the pump transition, the laser power calculated using the 2D CFD model is much higher than that obtained using the semi-analytical model. At high pump power, the heat convection out of the laser resonator is more efficient for the transverse case than the coaxial case, the temperature in the resonator is lower, and consequently the calculated laser power is higher. Optimization of the Cs DPAL parameters, using 3D CFD modeling, shows that applying high flow velocity and narrowband pumping, maximum lasing power as high as 40 kW can be obtained at pump power of 80 kW for transverse flow configuration in a pumped volume of ∼0.7 cm 3 .

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Section: F Spatial Variations Of the Pump And Laser Radiationmentioning

confidence: 99%

“…In spite of the considerable effort devoted to DPAL modeling [1,4,9,[11][12][13][14][15][16], only the kinetic processes in static DPALs, with uniform T and zero u, were studied. Spatial distribution of T in the static DPAL was first calculated in [14]; however, the influence of the temperature rise on the laser operation was not studied.…”

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamics modeling of subsonic flowing-gas diode-pumped alkali lasers: comparison with semi-analytical model calculations and with experimental results

2014

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“…14, σ 31 (ν p ) and σ 31,at are the stimulated emission and atomic cross section, respectively, in the line center and is the pump normalized Gaussian spectral distribution of full width at half maximum (FWHM) Δν p . 16 The laser intensities in both directions ± ( ) are assumed to be monochromatic and their spatial variations are described by equations similar to (11):…”

Section: Spatial Variations Of the Pump And Laser Radiationmentioning

confidence: 99%

“…In spite of the considerable effort devoted to DPAL modeling, 1,4,9,[11][12][13][14][15][16] only the kinetic processes in the static DPALs, with uniform T and zero u, were mainly studied. Spatial distribution of T in the static DPAL was first calculated in Ref.…”

Section: Introductionmentioning

confidence: 99%

Semi-analytical and CFD model calculations of subsonic flowing-gas DPALs and their comparison to experimental results

2015

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Application of two-and-three dimensional computational fluid dynamics (2D and 3D CFD) models to subsonic flowinggas DPALs is reported. The 2D model is applied to a DPAL with optical resonator-flow field coaxial configuration and the 3D model is applied to an optical axis transverse to the flow configuration. The models take into account effects of temperature rise and losses of alkali atoms due to ionization. The 2D CFD model is applied to 1 kW flowing-gas Cs DPAL [A.V. Bogachev et al., Quantum Electron. 42, 95 (2012)] and the calculated results are in good agreement with the measurements. Comparison of the 2D CFD to semi-analytical model [B. D. S. Rosenwaks, J. Opt. Soc. Am. B 30, 1118 (2013)] shows that for low pump power both models predict very close values of the laser power; however, at higher pump power, corresponding to saturation of the absorption of the pump transition, the laser power calculated using the 2D CFD model is much higher than that obtained using the semi-analytical model. At high pump power, the heat convection out of the laser resonator is more efficient for the transverse case than the coaxial case, the beam temperature is lower and consequently the calculated laser power is higher. Optimization of the Cs DPAL parameters, using 3D CFD modeling, shows that applying high flow velocity and narrowband pumping, maximum lasing power as high as 40 kW can be obtained at pump power of 80 kW for transverse flow configuration in a pumped volume of ~ 0.7 cm 3 .

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“…This new type of laser offers a new path to extremely high power, high beam quality and high efficiency laser system due to its high quantum efficiency, large cross section and gain medium characters. Many important studies followed the demonstration of the first DPAL, including theoretical model [2][3][4][5][6][7], demonstration of other alkali vapor lasers [2,8], hydrocarbon-free DPAL [8,9], Cesium vapor laser transversely pumped by multiple laser diode arrays [10] and a flowing DPAL with the ouptput power of about 1 kW [11]. 1 kW is by far the highest output power produced by DPAL.…”

Section: Introductionmentioning

confidence: 99%

Theoretical model and simulations for a cw exciplex pumped alkali laser

Huang

Tan

et al. 2015

Opt. Express

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The Exciplex Pumped Alkali Laser (XPAL) system, which is similar to DPAL (Diode Pumped Alkali vapor Laser), has been demonstrated in mixtures of Cs vapor, Ar, with and without ethane. Unlike DPAL, it uses the broadband absorption blue satellite of the alkali D₂ line, created by naturally occuring collision pairs. For example, Cs-Ar collision pairs have an absorption width which is as wide as the one of commercial semiconductor diode lasers. A continuous wave XPAL four-level theoretical model is presented in this paper. More factors are considered, such as the spectral dependence of pumped laser absorption for broadband pumping and the longitudinal population variation. Some intra-cavity details, such as longitudinal distributions of pumped laser and alkali laser, can also be solved well. The predictions of optical-to-optical efficiency as a function of temperature and pumped laser intensity are presented. The model predicts that there is an optimum value of temperature or pumped laser intensity. The analysis of the influence of cell length on optical-to-optical efficiency shows that a better performance can be achieved when using longer cell. The prediction of influence of Ar concentration and reflectivity of output coupler shows that higher optical-to-optical efficiency could be achieved if lower reflectivity of output coupler and higher Ar concentration are used. The optical-to-optical efficiency as high as 84% achieved by optimizing configuration with the pumped intensity of 5 × 10⁷ W/cm² presented shows that broadband pumped four-level XPAL system has a potential of high optical-to-optical efficiency.

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A three-level model for alkali metal vapor lasers. Part II: broadband optical pumping

Cited by 37 publications

References 24 publications

Computational fluid dynamics modeling of subsonic flowing-gas diode-pumped alkali lasers: comparison with semi-analytical model calculations and with experimental results

Computational fluid dynamics modeling of subsonic flowing-gas diode-pumped alkali lasers: comparison with semi-analytical model calculations and with experimental results

Semi-analytical and CFD model calculations of subsonic flowing-gas DPALs and their comparison to experimental results

Theoretical model and simulations for a cw exciplex pumped alkali laser

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