Abstract

There are some anomalies in Czochralski growth of alexandrite crystals, that is, as the melt becomes older it is hard to grow a clear crystal even when a good seed is used. Topographic observation and microscopic component BeAl₂O₄:Cr³⁺ crystals (three samples) grown in our laboratory was carried out by EPMA. The result shows that these three samples are not single crystals but poly­crystals in which there are grain boundaries, bubbles, and a large amount of inclusion gatherings. These cause scattering and absorption of light and spoil the transparency of the crystal. In fact, the so-called melt aging is poly-crystal formation. Analyzing the phenomena from many growth experiments and making technical experiments on how to avoid melt aging, we believe that in our technical conditions melt aging is caused mainly by unsuitable growth technology. However, the possibility that a solid solution range may exist around the BeAl₂O₄ stoichiometry should not be ruled out and further study is necessary. (Poster paper)

© 1986 Optical Society of America