High Quality Nd:YAG Laser Materials.

The crystal growth objectives of this program were two-fold to obtain high quality crystals of neodymium-doped YAG by means of size compensation with lutetium, and to obtain high quality crystals of neodymium YAG which contain sensitizing neodymium and 7 lutetium were successfully grown. The spectroscopic investigations of the neodymium lutetium YAG crystals showed that there was no change in the relative absorption intensities for any of the neodymium lines nor changes in the fluorescence branching ratios. No significant differences were noted in the lifetime of the neodymium in the neodymium lutetium YAG compared to neodymium YAG of the same neodymium concentration. Of the sensitizing ions investigated, high quality crystals were obtained with trivalent chromium and trivalent vanadium. Other ions, such as manganese, could not be incorporated in sufficient amounts to produce sensitization without adversely affecting crystal quality. From the spectroscopic evaluation, it appears that Mn4 is similar to Cr3 but less attractive because of the position of the pump bands. Weak energy transfer from Mn2 was observed but its usefulness is doubtful because of the inability to obtain high concentrations while maintaining crystal quality. Author