PHOTO-REFRACTIVE MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a photo-refractive material capable of obtaining high photosensitivity even without reduction treatment. SOLUTION: A photo-refractive material of single crystal of niobate containing terbium(Tb) or tantalate is a single crystal of lithium niobate(LiNbO3) whose molar ratio of [Li2O]/([Li2O]+[Nb2O5]) is in the range of 0.482 to 0.505 or single crystal of lithium tantalate(LiTaO3) whose molar ratio of [Li2O]/([Li2 O]+[Ta2O3]) is in the range of 0.482 to 0.505. As for this photo-refractive material, an amount of terbium to be added is 10 wt.ppm to 100 wt.ppm.