提拉法Tm：YAG晶体的生长缺陷研究

采用提拉法(CZ)生长了质量优异的Tm：YAG晶体．部分晶片在1000℃的空气气氛中退火25h．借助光学显微镜、扫描电子显微镜(SEM)，结合化学腐蚀法，对Tm：YAG晶体退火前后(111)面的缺陷特征进行了研究．Tm：YAG晶体(111)面的位错腐蚀坑呈三角形．在偏光显微镜下观察了退火前后Tm：YAG晶体(111)面的应力双折射．同时应用高分辨X射线衍射法测定了晶体的完整性．实验结果表明，长时间空气气氛下高温退火有效降低了晶体中总的位错密度，提高了晶体质量．

Tm:YAG crystal with high quality was grown by the Czochralski method. Some of the samples were annealed at 1000 degrees C for 25h in the air. Chemical corrosion was used to the slices of Tm:YAG crystal before and after air annealing. The etch pits in (111) plane were observed by Leitz optical microscope and scanning electron microscope (SEM). The shapes of etch pits located in (111) plane exhibit as a triangle structure. Stress birefringence of Tm:YAG slices as grown and after air annealing was investigated by polarization microscope. The lattice integrality of Tm:YAG crystal was investigated by high-resolution X-ray diffraction. The air annealing on slices for long time in high temperature can reduce the total density of the dislocations, and improve the quality of the crystals.