YAG CRYSTALS.

The design of the scaled-up growth stations necessary to produce the larger size NdYAG crystals was further improved until the mode of operation was considered as nearly optimized as could be achieved with the present system. Attention was then focused on learning how best to obtain the maximum operational control during the various stages of crystal growth. As experience with the new system was gained throughout the quarter, the quality of the crystals produced gradually improved. Most importantly, it was demonstrated that scale-up of crystal size can be accomplished with negligible change in the dimensions of the tube region. Therefore, the approach adopted should be capable of yielding larger size, higher quality NdYAG laser rods than it has heretofore been possible to produce. A total of eight crystals was delivered in completion of the second stage requirements.