Growth and Characterization of Large CaF_2 Single Crystals
Cui Chengjie(Changchun Institute of Opties and Fine Mechanics,Academia Sinica, 130022)Tomoya Ogawe(Kagushuin University, Faculty of Seience, Tokyo, Japan)
The B-S method to obtain large single crystals by control of solid-iiquid surface at the conical bottom of cruacible is discussed. The crystals grown by B-S technique need a heat processing to remove residual stress. It is discovered that there is a most favored temperature for annealing crystals in removal of residual stress This temperature is Below the one in the sense of ordinary heat processing. C-Z grown crystal dislocation distribution has been compared with B-S grown one. The result is found to be quite similar to the one received from semiconductor crystals The optical scattering centers in CaF_2 due to CaO or CaS and their selective precipitation are analysed, along with technique designed to eliminate above scattering centers.