CZOCHRALSKI RUBY

The experimental program on growth of ruby crystals by the Czochralski technique during this report period has emphasized improved control over temperature fluctuations and temperature gradients in the system, to increase still further the homogeneity of the product. A thorough evaluation of the optical and crystallographic properties of Czochralski ruby is presented, showing the uniformly high quality of the material when grown with preferred orientations. The optical quality of Czochralski ruby ranges from very good for 60 degrees and good for 90 degrees crystals to fairly poor for 0 degrees material. Both 60 degrees and 90 degrees crystals are of exceedingly high crystallographic perfection 0 degrees crystals are markedly inferior, exhibiting misorientations and dislocation densities of much greater magnitude. The fluorescence linewidth of Czochralski ruby is essentially independent of crystal orientation and is unaffected by annealing an apparent concentration dependence is observed, with higher linewidths at higher chromium concentration levels.