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Population inversion has been generated through the mixing of CO2 or N2O into a supersonic N2 flow, vibrationally excited by thermal means. Gain at 10.6μ, corresponding to the 001 → 100 transition in CO2, equal to 0.8%/cm has been measured in this medium. Using an optical cavity, oriented transverse to the flow, up to 60-W cw laser power at 10.6μ from CO2 was extracted from a 5-cm length by 1.2-cm2 cross-section active volume. When N2O was substituted for CO2 in the mixing region, cw laser emission was demonstrated at 10.8μ, corresponding to the 001 → 100 transition in N2O.

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Application of thermal dissociation of O 2 , developed within arc-heated gas mixtures, followed by a sufficiently rapid convection to preserve 0 atom concentrations and subsequent C~ injection, has generated efficiently a CO laser medium. In preliminary experiments, this pumping technique has produced a 34-W cw laser emitting over a band of vibration-rotation transitions from 4.9 to 5.71.1 from a 5-cm active transverse optical cavity.

Low-power cw laser emission from carbon monoxide excited by an rf discharge maintained directly within a supersonic (M ≈2.5) flow has been observed to consist predominantly of the lower-lying vibrational transitions. Optical power is extracted before the quasi-steady-state vibrational population distribution (dominated by vibrational-vibrational energy exchange) is achieved. P-branch laser emission has been observed on the ν=4→3, 5→4, and 6→5 vibrational transitions (λ = 4.89−5.04 μm) with a shifting to the higher vibrational transitions as the optical axis is translated downstream. A theoretical model coupling the effects of electron-impact pumping, molecular energy transfer, multiline laser emission, and nonequilibrium gas dynamics has been developed descriptive of this system. Representative model calculations are compared with experimental data.