Yb:GdVO_4晶体的缺陷研究

Investigation on Defects in Yb:GdVO_4 Crystal

Yb:GdVO4晶体是一种很好的激光材料,但缺陷会对晶体的激光性能产生严重影响,开展对该晶体的缺陷研究有助于提高晶体质量。采用提拉法生长了Φ25mm×20mm,掺杂浓度为2%的Yb:GdVO4晶体;分析了晶体的结构及其对晶体解理性的影响;采用化学腐蚀法,以盐酸、氢氟酸为腐蚀剂,对晶体的主要晶面进行了化学腐蚀实验,通过其腐蚀坑形貌对晶体中的位错和晶界进行了研究;对晶体进行了高分辨X衍射实验,结果表明晶体中存在镶嵌块结构;开裂及散射颗粒也为晶体中较常见缺陷。分析了缺陷的成因并提出了预防措施。

Yb ： GdVO4 crystal is an excellent laser material and studies on its defects were carried out to improve its quality since the defects have great influence on the laser performance of the crystal. Yb ： GdVO4 crystals with dimensions of φ 25 mm × 20 mm and a Yb-doping concentration of 2% were grown by the Czochralski method. Structure of the crystal and its influence on cleavage were investigated. Chemical etching experiments on the main facets were performed with the etching reagents of HCl and HF, and investigations on the dislocation and boundaries were carried out through the etch pits. The high resolution X-ray diffraction experiments confirmed the existence of a mosaic structure in the as-grown Yb： GdVO4 crystal. Such defects as cracking and scattering particles were also common with Yb ： GdVO4 crystal. Causes of forming and measures of precaution of these defects were discussed.