Colour centers in doped Gd3Ga5O12 and Y3Al5O12 laser crystals

Abstract The influence of rare earth and 3d impurities on the process of ionizing recharge of genetic defects under gamma-irradiation in Gd 3 Ga 5 O 12 and Y 3 Al 5 O 12 laser crystals has been studied by absorption spectroscopy. Impurities with stable trivalent states (Nd 3+ , Er 3+ , Sm 3+ , etc) do not change the character of absorption spectra of the colour centers formed during gamma-irradiation. Impurities (Cr, Fe, Ce) which can easily change valency during irradiation, compete with growth defects in trapping of the charge carriers generated by irradiation.