Diode laser spectroscopy of a fast-axial-flow CO2 laser active medium: vibrational distributions and plasma-chemical reactions

The diode laser spectrometer operating in the 4.5 μm region with a spectral resolution of about 10-4cm-1 was applied to investigate the active medium of a DC-excited fast-axial-flow CO2 laser. Detailed distributions of the CO2 molecules over the rotational and vibrational levels in a glow discharge plasma have been obtained, and corresponding temperatures have been derived. The vibrational distribution involves more than 30 levels from all vibrational modes of CO2. The bending and symmetric stretch temperatures were found to be equal, and approximately equal (within experimental error of 2-4%) to the rotational temperature.