Experimental and theoretical investigation of a closed-cycle gasdynamic CO2 laser

A report is given of the construction of a cw CO₂ gasdynamic laser with circulation of a mixture of the gases CO₂, N₂, and He around a closed loop. The operating parameters of the laser were: gas temperature ≤1200°K; compression ratio of the compressor ~6; gas flow rate ≤1 kg/sec. The measured gain was ~0.25 m^–1. It was shown that by using a closed cycle one can substantially raise the overall laser efficiency, an extremely important factor for the practical application of such devices in materials processing and in metallurgy.