Perfection of Ruby Laser Crystals

Ruby laser crystals grown by three different methods have been examined by x-ray topography and double-crystal rocking curves. Flame-fusion grown material is the least perfect. It usually has a few zones per centimeter that are tilted from the general matrix by 1 to 2 min of arc; the angular range of misorientation within the matrix is about 20 to 30 sec of arc. Flux grown ruby is intermediate in perfection with few or no gross imperfections and angular misorientation of 15 to 20 sec of arc. The most perfect ruby is grown by the Czochralski method. No gross imperfections have been observed; the angular misorientation is about 5 sec of arc over mm sized areas and 10 sec of arc over cm sized areas.