It is well-established that color centers (CCs) produced by ionizing radiation or short-wave radiation of the pump lamp, strongly influence the optical characteristics of yttrium-aluminum garnet single crystals. However, the possibility of positive effect of ionizing radiation on optical output of YAG lasers should not be rejected. This work addresses the effects of gamma radiation on performance of Er:YAG and CTH:YAG lasers. The direct influence of the CC on the processes of formation of the population inversion of the laser levels of Er:YAG and CTH:YAG crystals is emphasized.
