Mechanism of self-mode-locking in the active medium of CO2 lasers

It was found that, unless measures were taken to ensure single-mode emission, the dynamics of atmospheric-pressure CO₂ lasers resulted in mode-locking. This occurred primarily because of the high rate of the VV and RR exchange processes and because of the much higher (compared with nonpulsing radiation) gain due to the dependence of the gain-saturation radiation intensity on the degree of overlap of the fields of counterpropagating waves in the active medium of the laser.