Wide-band chemical laser utilizing both HF* and DF* excited molecules

Velikanov, S D; Elutin, A S; Zapol'skiĭ, A F; Konkin, D V; Kulikov, S. M.; Novikov, V. N.; Синицын, М. В.; Sukharev, S. A.

doi:10.1070/qe1991v021n02abeh003743

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…Technical efficiency ofthe laser amounted to 65% [19,20]. It's worth to note that in these days the maximum technical efficiency of200% at the specific output energy 30 JfI was obtained in our expeiiments with an electric-discharge chemical laser [16].…”

Section: Dependence Of Average Specific Output Energy Of Initiatedmentioning

confidence: 97%

Powerful chemical lasers

Borisov¹,

Velikanov²,

Zapol'skiy³

et al. 1998

SPIE Proceedings

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, Niznii Novgorod region Chemical reactions are abundant sources of energy varieties concentiated in their excited products. This experimental fact constitutes the basis ofthe conception stated by Poolany J.C. in 1961 [1], who offered to use exothermic chemical reaclions for population inversion. This conception was implemented by Russian scienhsts A.N.Oraevsky and V.L.Tal'roze in their works [2, 3,4,5]. it were they who formulated the major requirements which chemical reactions must meet for effective lasing.The way from theoretical consideration to experimental realization ofthe idea appeared to be very long. Only in 1965 J.V.Kasper and G.C.Pimentel obtained generation from excited HC1 molecules produced in a chain chemical reaction between molecular chlorine and molecular hydrogen [6].However, the possibility to obtain an active laser medium using a chain chemical reaction between fluorine which is the strongest oxidizer and the sfrongest reductant hydrogen didn't come true liii 1969. In his theoretical studies V L Tal'roze emphasized this reaction as one ofthe most promising [2]. It is interesting to note the fact that feasibility study oflasers based on chemical reactions coincides in lime with a sharp step-up in interest to the fluorine-hydrogen reaction stimulated by discovery of the absolutely new effect -branching of the chemical reaction -made by N. N. Semenov and A. I. Shilov in the course oftheir fluorine-hydrogen research [7]. It's necessary to note that strong chemical aggression and toxicity of fluorine caused fragmentary and chaotic character of investigations conducted nil 1962. Actually, study ofthe reaction was accompanied by great difficulties for experinienling staff, and the works dedicated to this chemical system could be counted on the fingers ofone hand.It was transpired that the reaction takes place at every pressure and temperature which could be realized under experimental conditions. A few electrons, light quantums, or simple collisions between reacting molecules and active volume's walls may be just enough to initiate it. It seemed impossible to prepare a mixture of fluorine with hydrogen in every volume, excluding the case ofa very little pressure ofthe main reactants amounting to a few tons, without having an explosion. One ofthe major signposts in this evolution was discovery ofthe mechanisms ensuring combustion limits in a mixture of fluorine with hydrogen, especially with regard to the last, at the expense of a homogeneous fri-molecular reaction of chain termination, which is the best developed at the presence of a third body. A cycle of works carried out by researchers of the Chemical-Physical institute of the Academy of Sciences of USSR (CPI AS USSR) gave the key to actualization ofpossible ways to handle development ofa fluorine-hydrogen reaction.Intensive study of this reaction was accomplished in due course at the CPI AS USSR, where in 1969 the collective guided by V.L. Tal'roze first obtained generation when population inversion was created using a fluorine-hydrogen react...

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Section: Dependence Of Average Specific Output Energy Of Initiatedmentioning

confidence: 97%

Powerful chemical lasers

Borisov¹,

Velikanov²,

Zapol'skiy³

et al. 1998

SPIE Proceedings

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Planar multifrequency mid-IR microwave-pumped lasers

Минеев¹,

Нефедов²,

Пашинин³

et al. 2020

Quantum Electron.

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The characteristics of planar repetitively pulsed diffusion-cooled HF, DF, HF – DF, Xe, and HF – DF – Xe(Kr) lasers pumped by a microwave discharge (2.45 GHz) are studied depending on the pump pulse duration (10 – 40 μs) and repletion rate (50 – 400 Hz), as well as on the composition and pressure of the working gas mixture (30 – 200 Torr) at low (to 0.6 L s−1) gas flow rates. It is demonstrated for the first time that a HF – DF – Xe gas-discharge laser may simultaneously operate as a HF – DF chemical molecular laser and a recombination laser based on xenon atom transitions and generate broadband (octave) radiation in the range 2.0 – 4.2 μm with an average output power of 43 mW and an efficiency of 0.9 %. With substitution of xenon for krypton, lasing in a HF – DF – Kr laser is obtained at wavelengths of 2.52 – 4.15 μm. Lasing in a HF – DF laser was achieved simultaneously in two spectral regions (2.7 – 2.9 and 3.6 – 4.2 μm) with an output power of ∼50 mW. It is found that a decrease in the pump pulse duration with a simultaneous increase in the pulse repletion rate for retaining the average energy deposition leads to an increase in the average output power and efficiency of the laser. At low pulse repetition rates (50 – 100 Hz) and a low gas mixture flow rate, helium buffer gas can be effectively substituted for neon. Operation of the Xe laser was achieved in the spectral range 2.03 – 3.65 μm with an average output power of 580 Mw at a pump pulse duration of 20 μs, a pulse repetition rate to 10 kHz, and a maximum efficiency of 55 %. The obtained experimental results demonstrate the possibility of creating broadband HF – DF – Xe lasers emitting in the frequency range 2 – 4 μm with a desired ratio of intensities in different spectral ranges.

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