The correlation between defects and photorefractive properties in Fe:In:LiNbO3 crystals

A series of Fe:In:LiNbO3 crystals with a varying content of In doping were grown by Czochraski technique. The absorption and infrared spectra measurement and two-wave coupling experiment are employed to study the effect of In doping on photorefractive properties of Fe:LiNbO3 crystals. The results indicate that the photorefractive properties can be greatly enhanced by proper level of In doping in Fe:LiNbO3. Among the four samples of Fe:In:LiNbO3 crystals, the Fe:In (2 mol%):LiNbO3 crystal exhibits the highest photorefractive sensitivity and the largest dynamic range (1.79 cm J−1 and 2.10, respectively) and can resist stronger laser intensity without distortion. In terms of ions’ site occupation model, the change of photorefractive properties due to different content of In ions existing in LiNbO3 is discussed systematically.