对LiNbO_3∶Fe∶Mn晶体非挥发全息存储的理论研究

Theoretical Study on Nonvolatile Holographic Recording in LiNbO_3∶Fe∶Mn

以双中心模型为基础,理论研究了LiNbO3∶Fe∶Mn晶体在稳态情况下的非挥发双光双步全息存储性能。采用数值方法,通过比较深(Mn2+/Mn3+)、浅(Fe2+/Fe3+)能级之间所有可能的电子交换过程,发现由隧穿效应引起的深浅能级之间直接电子交换过程对总的空间电荷场的大小起着决定性的作用。同时,这一电子交换过程对晶体非挥发全息存储性能也起着至关重要的作用。此外,还从理论上证实晶体中总的空间电荷场的大小主要由深能级的空间电荷场所决定。

Based on the two-center model, the steady-state nonvolatile two-step, two-color holographic recording performance with low-intensity continuous wave light for LiNbO3： Fe： Mn is studied theoretically. The contributions to the space charge fields from the different electron transfer processes between the deep trap centers （Mn^2＋/Mn^3＋ ） and the shallow-trap centers （Fe^2＋/Fe^3＋） are compared numerically. It is found that the direct electron exchange between the Mn^2＋/Mn^3＋ and the Fe^2＋/Fe^3＋ levels through tunneling effect dominates the amplitude of the total space charge field. This direct electron transfer process plays a key role in the two-step, two-color holography performance also. In addition, the amplitude of the space charge field of deep-trap centers （Mn^2＋/Mn^3＋ ） dominates the amplitude of the total space charge field is proved theoretically.