Nonvolatile holographic storage in LiNbO3:Mn:Ce:Cu crystal

Photorefractive lithium niobate (LiNbO3) is a promising recording medium for holographic data storage. In order to get non-volatile holograms, two-color or photo-gated holography that employs an independent pulsed or cw beam as a gating beam has been proposed to solved this problem. However from the reference we could find that the dynamic range M/# of two-color holography is lower. In this paper, triply doped Lithium niobate LiNbO3:Mn:Ce:Cu crystals and doubly doped Lithium niobate LiNbO3:Ce:Cu crystals were grown and the nonvolatile characteristic were investigated at different oxidation/reduction state and persistent holograms were recorded in these crystals. From the results, we found that the range of dynamic range M/# in a triply doped crystal is lager than that of doubly doped one. We also showed the effect of the oxidation/reduction state of the crystal on recording and readout responses. The experimental results show that there is an optimum oxidation/reduction state which resulting in the best dynamic range M/#.