重掺镁LiNbO_3∶Fe晶体的光谱与光折变特性研究

A STUDY OF SPECTRA AND PHOTOREFRACTIVE PROPERTY IN HEAVILY Mg-DOPED LiNbO_3∶Fe CRYSTALS

研究了重掺镁LiNbO3∶Fe晶体的透射光谱与光折变特性 .结果表明 ,LiNbO3∶Fe晶体在重掺镁后 ,镁离子把晶体中的铁离子“挤”入铌位是重掺镁LiNbO3∶Fe晶体抗光折变的原因所在 .在重掺镁 (≥ 5mol% )LiNbO3∶Fe的晶体中 ,作为施主中心的Fe2 +的特征吸收“台阶”的消失和 350 4cm- 1的OH吸收带的出现 ,都直接证明了铁离子从锂位进入了铌位 ,并以Fe3+Nb 的形式存在 .

The spectra and photorefraction property of heavily Mg doped LiNbO 3∶Fe crystals have been studied.The results demonstrate that Mg ion ‘squeezed’ Fe ion into Nb site is the cause of heavily Mg doped LiNbO 3∶Fe crystals resisting photorefraction.The disappearance of characteristic absorbtion ‘step’ as donor centre Fe 2+ and the appearance of 3?504?cm -1 absorption peak directly demonstrat that Fe ion is ‘squeezed’ into Nb site and takes on Fe 3+ Nb form in heavily Mg doped(≥5?mol%) LiNbO 3∶Fe crystals.