基于晶体中线性偏振波的耦合波理论以及光折变效应的能带传输模型,求出了体全息存储系统中光折变晶体动态范围的解析表达式。以LiNbO3:Fe和BaTiO3晶体为例,讨论了读写光束与晶体作用的几何结构形式、晶体掺杂量大小及其氧化还原状态等因素对动态范围的影响。研究发现,对两种晶体来说,掺杂浓度越大、氧化程度越深,则可获得的动态范围越大。在BaTiO3晶体中要获得最大动态范围,则光栅矢量与晶轴C之间的最优夹角应随参考光与信号光之间夹角的不同而不同。

Based on the coupled mode theory for polarized waves inside crystals and the linearized band transport model for photorefractive effect, the analytical expression of the dynamic range parameter, M/#, of a photorefractive crystal in a volume holographic momory is derived. Taking LiNbO 3:Fe and BaTiO 3 as examples, we discuss the influence of the impurity doping level, oxidation reduction state and geometric configuration of coupling beams on the dynamic range performance. For both crystals we found that the denser the donor concentration and the higher the oxidation level, the larger the maximum possible dynamic range. For BaTiO 3 crystal the optimum angle between grating wave vector and optical axis should vary with the angle between signal and reference beams.