CE-3+ CENTERS IN Y3AL5O12 (YAG) SINGLE-CRYSTALS .2.

The absorption spectra due to the 4f --> 5d transitions in Ce3+ centres have been measured with the use of YAG:Ce3+ single crystals with a lattice concentration [Ce3+]L = (1.28 +/- 0.05)%. The data are almost independent of the spectral behaviour of a reference spectrum whose absorption constants are approximately 2 cm-1 at the highest, since the absorption constants of 129 cm-1 and 50 cm-1 have been derived, relative to the reference spectrum, at the strongest peaks in the dy and de regions, respectively. The absorption area 32.3 cm-1 eV measured on the strongest dy-band suggests that about a quarter of the Ce-concentration, [Ce3+]M, added in the mixture of the starting powders is incorporated into [Ce3+]L as YAG:Ce3+. It is found that the highest-energy lying d-epsilon band is located at 6.06 eV, in agreement with 6.07(0) eV for the corresponding band peak in the excitation spectrum and that the ratio of the absorption area of d-gamma to that of d-epsilon is nearly 2:3.