Photorefractive features of non‐stoichiometry codoped Hf:Fe:LiNbO₃ single crystals

Abstract

. The mechanisms of the photorefractive resistant ability increase and the absorption band shift have been discussed. The exponential gain coefficient (Г) of the crystals was measured with two-beam coupling method and the effective charge carrier concentration (N eff ) was calculated. The results show that Г and N eff increase with the accretion of [Li]/[Nb] ratio. The temperature effect of codoped Hf:Fe:LiNbO 3 crystals was also studied, it was found that the exponential gain coefficient increase dramatically at about 55°C, 70°C and 110°C, this is due to the inner electric field which is resulted from structure phase change.