**Liyun Xue 1, Hongde Liu 1,\*, Dahuai Zheng 2, Shahzad Saeed 1, Xuying Wang 1, Tian Tian 3, Ling Zhu 1, Yongfa Kong 1,2,\*, Shiguo Liu 1, Shaolin Chen 2, Ling Zhang <sup>2</sup> and Jingjun Xu 1,2**


Received: 2 April 2019; Accepted: 25 April 2019; Published: 28 April 2019

**Abstract:** We mainly investigated the effect of the valence state of photorefractive resistant elements on the photorefractive properties of codoped crystals, taking the Zn and Mo codoped LiNbO3 (LN:Mo,Zn) crystal as an example. Especially, the response time and photorefractive sensitivity of 7.2 mol% Zn and 0.5 mol% Mo codoped with LiNbO3 (LN:Mo,Zn7.2) crystal are 0.65 s and 4.35 cm/J at 442 nm, respectively. The photorefractive properties of the LN:Mo,Zn crystal are similar to the Mg and Mo codoped LiNbO3 crystal, which are better than the Zr and Mo codoped LiNbO3 crystal. The results show that the valence state of photorefractive resistant ions is an important factor for the photorefractive properties of codoped crystals and that the LN:Mo,Zn7.2 crystal is another potential material with fast response to holographic storage.

**Keywords:** lithium niobate; optical storage materials; photorefractive materials
