The photorefractive effect in Indium-doped litium niobate crystal was studied. We found that the enhanced photorefractive sensitivity could be realized in the so-called photorefractive resistance lithium niobate crystals, even higher than the well-known iron doped ones. We explained the unusual qualitatively. The experimental result enriches us the knowledge of the properties of doped lithium niobate crystals and provides some advice in growing specific crystal.
We investigated the infrared spectra of the optical damage caused by laser diode at 808 nm in iron-doped lithium niobate crystals. The spectra show that the OH<sup>−</sup> absorption band in the region of the optical damage exhibits a structure consisting of three peaks. Comparing to the spectra at the non-damage region the main peak moves to red. The result will be helpful to microphotonic device applications.