Automated tuning of a CO2 laser to a required oscillation line without a spectral instrument

The method is proposed for tuning CO₂ laser to a required oscillation line without a spectral instrument based on the coincidence of transition frequencies belonging to different vibrational–rotational bands of the CO₂ molecule. This coincidence leads to the anomaly in the gain distribution over rotational sublevels, thereby affecting the laser output parameters. The method was successfully applied to a completely automated low-pressure, longitudinal-discharge cw CO₂ laser and a pulsed TEA CO₂ laser.