Line shape parameter analysis of individual vibrational-rotational transitions in a CO2laser amplifier

Applying the measured incremental irradiance gain per unit plasma length for various input irradiances to the analytical formulas for a partially homogeneously broadened, saturated gain medium, the line shape parameters such as the small-signal gain, the saturation parameter, and the ratio of the Lorentzian to Doppler linewidths are obtained for individual vibrational-rotational transitions of a CO
2
laser amplifier. It is found that the homogeneous broadening becomes predominant across the lines with a higher gain, while the inhomogeneous broadening is emphasized across the remote lines with a lower gain from the central line for both
10 P
and
R
branches. Pressure and discharge-current dependence on the lineshape parameter are also investigated for the typical two lines, i.e.,
10 P
-20 and -12 lines, together with discussions.