Heuristic method for evaluating COIL performance

Chemical oxygen-iodine lasers (COIL) are attractive for diverse industrial applications because they are capable of high efficiency, high power operation, and because the 1.315 m wavelength can be transmitted through fiber optics and couples efficiently with most metals. Conventional COILs are pumped with O 2 ͑ 1 ⌬͒ that is generated by reaction of Cl 2 in a basic H 2 O 2 solution. Current trends in pumping COILs involve producing the O 2 ͑ 1 ⌬͒ in electric discharges, thereby circumventing the hazards, complexity, and weight associated with pumping and storing caustic liquids. In this work, we have investigated the scaling of O 2 ͑ 1 ⌬͒ yields with specific energy deposition in He/ O 2 mixtures in flowing radio frequency (rf) discharges at pressures of a few to tens of Torr using a global plasma kinetics model. We found that O 2 ͑ 1 ⌬͒ yield increases nearly linearly with specific energy deposition in O 2 molecules up to a few eV per molecule, with yields peaking around 30% by 5 -8 eV. Further increases in specific energy deposition serve only to increase O 2 dissociation and gas heating, thereby reducing the O 2 ͑ 1 ⌬͒ yield. We also found that variations in peak yields at a given specific energy deposition are caused by secondary effects resulting from dilution, pressure, and power level. We show that these secondary effects alter the O 2 ͑ 1 ⌬͒ yield by shifting the O 2 ͑ 1 ⌺͒ /O 2 ͑ 1 ⌬͒ ratio.

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“…(16)], dissociation [Eqs. (17) and (18)], and superelastic deexcitation [Eq. (19)] begin to dominate.…”

Section: Scaling Of O 2 "mentioning

confidence: 99%

O 2 ( Δ 1 ) production in He∕O2 mixtures in flowing low pressure plasmas

Stafford

Kushner

2004

Journal of Applied Physics

270

200

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“…The yield of O 2 ͑ 1 ⌬͒ for optical transparency as a function of temperature is Y OT =1/͓1 + 1.5 exp͑403/ T͔͒. 17 Note that the backward rate is slower, K eq larger, and Y OT lower as T is decreased.…”

mentioning

confidence: 99%

Continuous-wave laser oscillation on the 1315nm transition of atomic iodine pumped by O2(a1Δ) produced in an electric discharge

Carroll

Verdeyen

King

et al. 2005

Applied Physics Letters

107

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Laser action at 1315nm on the I(P1∕22)→I(P3∕22) transition of atomic iodine is conventionally obtained by a near-resonant energy transfer from O2(a1Δ) which is produced using wet-solution chemistry. The difficulties in chemically producing O2(a1Δ) has motivated investigations into purely gas phase methods to produce O2(a1Δ) using low-pressure electric discharges. In this letter, we report on the demonstration of a continuous-wave laser on the 1315nm transition of atomic iodine where the O2(a1Δ) used to pump the iodine was produced by a radio-frequency-excited electric discharge. The electric discharge was sustained in a He∕O2 gas mixture upstream of a supersonic cavity which is employed to lower the temperature of the continuous gas flow and shift the equilibrium of atomic iodine in favor of the I(P1∕22) state. The laser output power was 220mW in a stable cavity composed of two 99.99% reflective mirrors.

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“…͑14͒. The flow conditions within the laser cavity are deduced by analysis and calculation of the RotoCOIL experiment 11,14 : The flow temperature T is 167K, the entrance pressure P is approximately 4 torr, the small signal gain g 0 ϭ 0.0068 cm…”

Section: Resultsmentioning

confidence: 99%

“…10 There are also great disparities in the chemical efficiencies of supersonic COIL experiments. 11 Herein a spectral line broadening ͑SLB͒ model is one of the key factors in explaining the disparities, and an appropriate SLB model can play an important role in optimizing the adjustable parameters. Thus it is important to examine and develop different SLB models in the COIL.…”

Section: Introductionmentioning

confidence: 99%

Performance Analyses of Flowing Chemical Oxygen-Iodine Laser

Zhi

2003

Appl. Opt.

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A modified simplified rate-equation model that utilizes the Voigt profile function and another gain saturation model deduced from the kinetic equations are presented for performance analyses of a flowing chemical oxygen-iodine laser. Both models are adapted to both the condition of homogeneous broadening and that of inhomogeneous broadening being of importance and the condition of inhomogeneous broadening being predominant. Effects of temperature and iodine density on the output power and on variations of output power, optical intensity, and saturation intensity with flow distance are presented as well. There are differences between results of two models, but both qualitatively agree with known results.

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Heuristic method for evaluating COIL performance

Cited by 36 publications

References 3 publications

O 2 ( Δ 1 ) production in He∕O2 mixtures in flowing low pressure plasmas

O 2 ( Δ 1 ) production in He∕O2 mixtures in flowing low pressure plasmas

Continuous-wave laser oscillation on the 1315nm transition of atomic iodine pumped by O2(a1Δ) produced in an electric discharge

Performance Analyses of Flowing Chemical Oxygen-Iodine Laser

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