双掺杂LiNbO_3:Fe:Mn全息存储动力学

THE DYNAMICS OF HOLOGRAPHIC STORAGE IN DOUBLY DOPED LiNbO_3:Fe:Mn

建立了包括扩散、漂移和光伏打效应三种输运机制 ,小信号光强、小调制度近似下描述双掺杂LiNbO3 :Fe:Mn晶体用双色光进行全息存储的动力学的耦合微分方程组 ,数值求解并解释了晶体光存储的时间动态发展过程 .在此基础上 ,分析了晶体的氧化还原程度对全息存储过程的影响 ,只有在晶体总的受主数密度Na(即Fe3 + 和Mn3 +的数密度之和 )大于铁离子数密度N2 的条件下 ,双掺杂LiNbO3 :Fe:Mn晶体全息存储才能达到非破坏性存储的目的 .经过光固定的光栅的衍射效率随氧化增大 ,光折变灵敏度随氧化而减小 ,要获得高衍射效率就必须以降低光折变灵敏度为代价 .在掺铁浓度一定的情况下 ,掺锰浓度越高 。

Considering the three transport mechanisms of diffusion, drift and the photovoltaic effect, we set up a set of coupling differential equations that describe the dynamics of the two color holographic storage in doubly doped LiNbO 3:Fe:Mn in the case of small signal and modulation, and solve the equations to explain the time dynamic development process of holographic storage by using the numerical calculation method. On the basis of these results, we analyze the effect of oxidation reduction on the process of holographic storage, the non volatile holographic storage is realized only if the sum N a of number density of the acceptors (Fe 3+ and Mn 3+ ) is larger than the number density of iron ions N 2 . Diffraction efficiency of fixed grating increases with oxidation, photorefractive sensitivity decreases with oxidation, higher diffraction efficiency is at the cost of lower photorefractive sensitivity. When the concentration of doped iron is constant, the higher the concentration of doped manganese, the larger the effective dynamic range of state of oxidation\|reduction is, in which holograph can be saved permanently.