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The vibrationally excited oxygen in the O 2 (a 1 Δ g )–I mixture by emission spectroscopy was detected. The analysis of a luminescence spectra of oxygen molecules on the O 2 (b 1 Σ g + , v = i )→O 2 (X 3 Σ g − , v ′ = i ) transitions ( i =0,1,2) has shown, that ≈22% of O 2 (b 1 Σ g + ) molecules are excited with v =1 and ≈10% with v =2. It is shown theoretically, that a mean number of vibrational quanta per one molecule in each of components O 2 (X 3 Σ g − ), O 2 (a 1 Δ g ) and O 2 (b 1 Σ g + ) is approximately equal because of fast EE energy exchange between oxygen molecules and reaches 0.3.

A simplified two-level generation model predicts that power extraction from an cw oxygen-iodine laser (OIL) with stable resonator depends on three similarity criteria. Criterion τ d is the ratio of the residence time of active medium in the resonator to the O 2 ( 1 Δ) reduction time at the infinitely large intraresonator intensity. Criterion Π is small-signal gain to the threshold ratio. Criterion Λ is the relaxation to excitation rate ratio for the electronically excited iodine atoms I( 2 P 1/2 ). Effective power extraction from a cw OIL is achieved when the values of the similarity criteria are located in the intervals: τ d =5-8, Π=3-8 and Λ≤0.01.

Experiments with a flow cell apparatus imitating conditions of oxygen-iodine laser, equipped with a chemical jet singlet oxygen generator and an electric discharge iodine generator have been performed. I2 and CH3I in the flow of Ar were used as atomic iodine precursors. The distributions of the electronically excited species along the flow were examined detecting their optical emissions. A straightforward comparison of two methods of oxygen-iodine medium production - conventional, by means of I2 dissociation in the singlet oxygen flow and with iodine atoms produced externally in the electric discharge - was performed. It was found that stored electron energy lifetime had been about 30% longer, when iodine was produced from CH3I in the discharge, compared to the conventional I2 dissociation in the singlet oxygen flow. It was observed that maximums of the I(2P1/2) and I2(B) concentrations had shifted to the nozzle plane, when I2 in Ar carrier was subjected to the glow discharge, pointing to a nearly twofold increase in the I2 dissociation rate. Contrary to the known results for low iodine and singlet oxygen concentrations, squared dependence of the amplitude of the I2(B) luminescence maximum with I(2P1/2) concentration was observed in the dissociation region for both methods of iodine production.

The analysis of a luminescence spectra of oxygen molecules on O2(b1Σg,υ")→O2(X3Σg-υ") transitions has shown, that vibrationally excited O2(b1Σg+) molecules up to υ=5 are generated in the active medium of chemical oxygen-iodine laser (COIL). Comparison of experimental and calculated results has shown that 4.5 vibrational quanta of oxygen are formed in the active medium of COIL under the deactivation of one singlet oxygen molecule. Dependencies of the threshold of O2(α1Δg) yield and gain on relative population of vibrationally excited oxygen are studied. The threshold of O2(α1Δg) yield increases with rising of the relative population of vibrationally excited oxygen and can be some percents more than it was considered before. The gain coefficient weakly depends on the relative population of vibrationally excited oxygen.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

It is experimentally shown that more than 20% of O2 molecules in chemical oxygen iodine laser (COIL) active medium are vibrationally excited. Calculations show that approximately 4.5 vibrational quanta are formed under deactivating of one singlet oxygen O2(1Δ) molecule. Dependencies of threshold O2(1Δ) yield and gain on relative population of O2(1Δ,υ) are presented. The threshold O2(1Δ) yield increases with rising of the relative population of vibrationally excited oxygen and it can be some percents more than was considered before. The gain coefficient of COIL weakly depends on the degree of vibrational excitation of oxygen.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An H2 - F2 amplifier initiated by radiation from a pulsed hydrogen fluoride laser is studied theoretically. Numerical calculations are made by taking into account the inhomogeneity of initial HF concentration appearing upon preparation of the laser mixture in experiments. The dependence of the specific laser output energy from a distance x from the radiation input to the amplifier medium for mixture H2:F2:O2:He = 100:600:30:100 Torr is obtained. Change of initial pressure of HF molecules in the mixture on the distance x was described by the expression po + C sin(2πx/d ), where Po = 0.1 - 0.5 Torr, d = 10 - 20 cm, C is the amplitude of deviation of HF pressure from its mean value. The theoretical specific output energy periodically depends on x according to the law of change of pressure HF. The energy gain (ratio of the energies of the output and initiating laser radiation) is equal to 5 for an amplification length 4 m at po = 0.1 Torr and C /po = 5%.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The kinetics model of chemical oxygen-iodine laser (COIL) active medium taking into account EE, EV, VV, VT energy transfer processes was proposed. The O2 molecule distribution on the vibrational levels in COIL was calculated. It is suggested that the involving of vibrationally excited O2(a ) into pooling reaction can increase the rate of stored in singlet oxygen electronic energy in COIL medium. Approximately 50% of relaxed O2(a ) energy transfers into thermal energy.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The vibrationally excited oxygen in O2(a 1Δg)-I mixture was detected by emission spectroscopy. The analysis of a luminescence spectra of oxygen molecules on O2(b 1Σg+,υ') → O2(X3Σg-,υ") transitions has shown, that vibrationally excited O2(b 1Σg+) molecules up to υ=5 are generated in the active medium of chemical oxygen-iodine laser (COIL). The highest values of relative O2(b 1Σg+,υ=1) population of 22% and O2(b 1Σg+,υ=2) of 10% are reached for I2 content in an oxygen flow ≈1%. It is shown theoretically, that the relative populations of O2(X3Σg-), O2(a 1Δg) and O2(b 1Σg+) molecules at the first and the second vibrational levels are approximately equal because of fast EE energy exchange between oxygen molecules. Up to 20% of oxygen molecules in COIL active medium are vibrationally excited.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.