Influence of the isotopic composition of the active medium on the parameters of radiation from CO2 lasers

A theoretical investigation was made of the lasing characteristics of CO₂ lasers with active media containing molecules of ¹²C¹⁶O₂, ¹³C¹⁶O₂, ¹²C¹⁸O₂, and ¹²C¹⁶O¹⁸O. The dependences of the lasing efficiency on the input energy, the Q factor of the resonator, and the degree of enrichment of carbon dioxide with a particular isotope were determined. The calculations were carried out allowing for the partial overlap of the lines due to different vibrational–rotational transitions and use was made of new data on the probabilities of spontaneous emission from the investigated molecule. The results were in good agreement with the published experimental data.