Pumping Mechanism of CO2 Laser and Formation Rate of CO2 from CO and O

The pumping mechanism of a high-current pulsed CO2 laser has been investigated. It was found that there is a time delay of the laser pulse behind the current pulse. From the dependence of the time delay on the plasma parameters, such as electron density, electron temperature, gas temperature, gas pressure, and emission of oxygen atomic line (7771 Å), it can be shown that during the current pulse, the CO2 is totally dissociated into CO and O. The subsequent recombinations of CO and O into CO2 are responsible for the pumping of the upper level of the CO2 laser (10.6 and 9.4 μ). The time delay between the current pulse and laser pulse is thought to be due to the time required for CO and O to recombine to reach the threshold population for lasing for the particular optical cavity. The threshold upper level population is obtained by knowing the Q value of the optical cavity, wavelength of the laser line, and linewidth of the radiation line. By equating the amount of CO2 formed during the delay time to the threshold upper laser population, the reaction rate of CO+O→CO2 is thus obtained. The agreement between the rate obtained and previously determined supports the proposed pumping mechanism.