Optical damage resistance of In:Fe:LiNbO3 crystals related to the defect structure

A series of In:Fe:LiNbO3 crystals with various concentration of In2O3 doping were grown in an air atmosphere using the Czochralski method. Spectroscopic properties (fundamental absorption edge, OH vibrational band) were used for an exploration of the defect structure. Light-induced scattering and direct observation of the transmitted laser beam distortion were used to characterize the optical damage. It was found that the threshold intensity of In (3 mol%):Fe:LiNbO3 was 2 orders of magnitude higher than that of Fe:LiNbO3 and was able to withstand higher power level. The increase in damage resistance could be attributed to the Fe3+ losing their electron acceptor properties and therefore an increase in photoconductivity. (C) 2004 Elsevier B.V. All rights reserved.