Investigation of Lithium Niobate Photorefractive Properties by Photorefractive Light Scattering and Raman Spectroscopy

摘要

The changes of photorefractive light scattering (PRLS) in time and Raman spectra are investigated in congruous lithium niobate single crystals doped with "unphotorefrac-tive " Gd~(3+) cations. The best cation concentration is determined for the biggest PRLS. When the doping cations concentration increases, the intensity of Raman spectra lines prohibited by the selection rules for the considered scattering geometries first decreases then increases. This effect shows the photorefraction decrease, which might be caused by the cation sublattice units ordering along the polar axis. This leads to the decrease of amount of containing located electrons defects which determine the photorefractive effect.