CAJ | 학술논문

本文研究了低光强下锂组分对纯铌酸锂晶体的可见光折变、紫外光致吸收及紫外光折变性能的影响,发现了光折变中心种类和数量随晶体组分的渐变行为.在组分较低的同成分晶体中,大量本征缺陷形成Q极化子,因而在可见光波段表现出较弱的光生伏打效应;在组分较高的近化学计量比铌酸锂晶体中,双极化子是主要光折变中心,从而引起较高的光生伏打电场.而纯铌酸锂晶体的紫外光致吸收以及紫外光折变性能则具有相似的组分依赖关系.它们随组分的增加过程可分为两个不同的阶段:当组分小于49.70 mol%时,随组分增加缓慢升高,而当组分高于49.70 mol%时,随组分突然猛增并迅速升高.上述实验结果也可采用本征缺陷由Q极化子主导向双极化子主导的渐变过程进行解释.
본문연구료저광강하리조분대순니산리정체적가견광절변、자외광치흡수급자외광절변성능적영향,발현료광절변중심충류화수량수정체조분적점변행위.재조분교저적동성분정체중,대량본정결함형성Q겁화자,인이재가견광파단표현출교약적광생복타효응;재조분교고적근화학계량비니산리정체중,쌍겁화자시주요광절변중심,종이인기교고적광생복타전장.이순니산리정체적자외광치흡수이급자외광절변성능칙구유상사적조분의뢰관계.타문수조분적증가과정가분위량개불동적계단:당조분소우49.70 mol%시,수조분증가완만승고,이당조분고우49.70 mol%시,수조분돌연맹증병신속승고.상술실험결과야가채용본정결함유Q겁화자주도향쌍겁화자주도적점변과정진행해석.
The influence of Li composition on VIS-light photorefraction, UV-light-induced absorption and UV-light photorefraction in pure LiNbO_3 crystals at low light intensity was investigated. The experimental results indicate that different defects dominate the photorefractive centers of pure LiNbO_3 with varied compositions. For VIS-light photorefraction, Q polarons are introduced to explain the weak photovoltaic effect in LiNbO_3 with low composition, and bipolarons are considered to be responsible for the enhanced photovoltaic field in LiNbO_3 with high composition. It is also found that the UV-light-induced absorption and UV-light photorefraction have similar composition dependence. They increase slowly with the composition below 49.70 mol% but boosts up very rapidly above this critical composition. These findings are explained by the two different stages in the evolution of photorefractive centers during the increase of the crystal composition, which also proves our suggestion that different defects dominate the photorefractive centers of pure LiNbO_3 with varied compositions.