Diagnostics of the active medium of a CO2 laser on the basis of the values of the gain at the wavelengths of 10.4 and 9.4 μm

The distribution of the saturation values of the gain between the P- and R-branch lines of the 10.4 and 9.4 μm transitions was determined experimentally for a cw gas-discharge CO₂ laser of conventional construction. A method was developed for using such a distribution to find the populations of the vibrational levels, the gas T and vibrational T₂ and T₃ temperatures, and the concentration of CO₂ in the operating laser. The method could be used even in the case of a large difference between the temperatures T and T₂. A comparison of the results obtained in the presence or absence of lasing made it possible to determine the effectiveness of pumping and relaxation of the active levels.