The growth of perfect YAP crystals doped with Nd, Cr and Ce in resistant furnace, reductive conditions and high vacuum and Mo crucible are described. The growth conditions for decreasing: decomposition of crystals, iron content and twinning are found. Distribution coefficients of dopants, some spectral and generation properties of the crystals were measured.

AbstractSpectroscopic and laser properties of YAG:Nd and YAP:Nd grown from the nonstoichiometric melts or those containing Mo and Fe impurity were compared. YAG:Nd grown from the melt with surplus of Y2O3 and annealed in H2 at ∼ 1400 °C have an increased laser performance. Mo admixture in hydrogen annealed YAP:Nd laser crystals suppresses effectively the detrimental action of iron impurity.

Spectroscopic properties of undoped YAG and YAP grown under reducing protective atmosphere were compared. Blue (with F centre) or brown (with 0 centre) varieties both of the materials were prepared in the dependence of the Al O :Y O ratio in the melt. Colour intensity depends on the H O:H ratio in the protective atmosphere and on the sign of electrical potential above the melt level. The coloration may be easily removed by an annealing at > 1200–1400 °C. All the irregularities of the colourations or their remowing by annealing may be attributed to the presence of impurities.

Al O and YAG crystals were purified from traces of iron by the growth in reducing atmosphere. Luminescence output of such materials was substantially increased, but some undesirable properties as transient colour centre formation in YAG: Nd and low damage threshol of ruby laser rods were observed. Minimum concentration of iron ions which drastically change spectral properties of oxide crystals seems to be ⪅ 10 wt%.

The luminescence intensity of Yttrium aluminium garnet activated by the Ce3+ (YAG∶Ce3+) under cathode-ray excitation depends on the preparation method and content of some dopants. Samples containing Fe, Pt, Ir or some colour centre, respectively, show relatively low luminescence. The maximum luminescence intensity was obtained with the Czochralski method grown single crystals in 98% Ar+2% H2 atmosphere which were sensitized by oxygen annealing followed by treatment at 1500 °C in molybdenum container using a wet hydrogen atmosphere.