Recharging processes of active ions and radiation defects in some laser crystals doped with RE and TM ions under proton irradiation

Recharging processes of transition metal ions (Cr, Fe, Cu) and rare-earth ions (Dy, Nd, Er, Pr) in some oxide laser crystals: Y3Al5O12, LiNbO3, SrLaGa3O7, Gd3Ga5O12 and YAlO3, and, also radiation defects arising in these materials under influence of gamma, electron and proton irradiations and annealing were analyzed. Special attention was paid to proton irradiations that were did for fluencies of 1012-1016 cm−2. To show changes in optical properties of the materials additional absorption spectra were obtained and analyzed. To avoid different initial defect structure of the crystals, we annealed them in the air or in hydrogen against proton irradiation. The same type of color centers after proton irradiation we found for all investigated oxides as previously registered for gamma irradiated the crystals. But the limit was found of the behavior, 1-5 × 1014 cm−2 (dependently on the crystal) fluency, over which Frenkel defects are formed. We found crystals more resistant to proton irradiation (GGG) and dopants very sensitive to the type of ionizing radiation (Fe, Cu, Cr).