Nonvolatile photorefractive properties in triply doped stoichiometric Mg:Fe:Mn:LiTaO₃ crystals

We have grown triply doped Mg:Fe:Mn:LiTaO₃ crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep (Mn) and shallow (Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg²⁺ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.