抄録
Single crystal materials being used in various fields of electro-optics are briefly reviewed. Methods to grow single crystals of these materials are surveyed and critically reviewed, and the advantages and disadvantages in Czochralski method are discussed. It is stressed that systematic approach should be taken, and that detailed investigations to correlate between growth parameters and the defects in the pulled crystals are especially important in order to find the optimum growth conditions under which high quality crystals of a particular material may be obtained. The origins of various possible difficulties in pulled crystals, such as diametrical instability, carck, cavity, subgrain, growth straie, growth core, growth cell, scattering center, dislocation and so on are discussed, and the countermeasures for those defects are pointed out. In fact, high optical quality crystals of Gd_2 (MoO_4)_3 and (Sr, Ba)Nb_2O_6 have been successfully grown by such a optimization process.
