The influence of CO and CO2laser performance

Impurities are necessary to achieve considerable CW laser action in CO
2
since in pure CO
2
the disintegration of the lower laser level is too slow to maintain a substantial population inversion. The dissociation product CO, provided by the discharge itself if initially pure CO
2
is used in a sealed system, enhances the gain mainly because of its effectiveness in accelerating the relaxation of the first level of the bending mode to which the lower laser level relaxes. The characteristic time for energy exchange between these two levels is
20 \pm 5 \mu
s at 1 torr, 400°K. Experiments in He-CO
2
mixtures support the assumption that the main influence of CO is to accelerate the decomposition of the lower laser level.