Doubly doped lithium niobate crystals

摘要

This invention relates to the field of materials of the photorefractive crystal. The composition of these crystals is Li_1−xNb_1+yO₃: Fe_m, M_n, where M can be magnesium, indium, or zinc; when using q to denote the ion valence of M (q=2 when M is Mg or Zn, and q=3 when M is In), the values of x, y, m, and n are in the range of 0.05≦x≦0.13, 0.00≦y≦0.01, 5.0×10^−5≦m≦7.5×10^−4, and 0.02≦qn≦0.13. This invention greatly improves the photorefractive properties of LiNbO₃ crystals: makes it have a high diffraction efficiency (more than 68%), a fast response speed for photorefraction (an order of magnitude faster than iron doped LiNbO₃), and a high resistance to optical scattering (the light intensity threshold to photorefractive fan scattering near two orders of magnitude larger than LiNbO₃: Fe). This invention is an excellent three-dimensional optical storage material and has a vast potential market.