THERMODYNAMIC ANALYSIS AND FORMATION ENTHALPY CALCULATION OF OXYGEN VACANCY DEFECT IN DOPED LITHIUM NIOBATE CRYSTALS

Based on the thermodynamic analysis of oxygen vacancy defects in lithium niobate (LiNbO₃ (LN)) and the data of thermogravimetric experiment, the formation enthalpies of congruent and several rare-earth (RE) doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping with valence-changeable RE ions. The experimental results were discussed and a new reduction process for photorefractive LN crystals at a relatively low temperature was proposed, and the reduction-treated crystals showed good effect in practical use.     

LiNbO3：Mg,Er晶体的光谱性质

铌酸锂(LiNbO_3)晶体是优良的电光和非线性光学材料。自从该晶体的光折变损伤被克服以来,MgO与稀土离子双掺LiNbO_3晶体的研究开始活跃起来,并首先在LiNbO_3:Mg,Nd中获得1.093μm和自倍频0.546μm激光输出。Er~(3+)是重要的激活离子,可在十几个通道实现激光输出。作者曾在文献[2]和[3]中首次报道了LiNbO_3,Er晶体生长特性及表面分析的研究结果,本文将介绍该晶体的光谱特性,并讨论LiNbO_3:Mg,Er晶体作为激光材料的可能性。