双中心全息记录的矢量分析与记录方向优化

对描述双掺杂晶体非挥发性全息记录动力学过程的Kukhtarev方程进行了矢量分析,分析中考虑了体光生伏特效应和外加电场的作用。在小信号近似的基础上给出了双中心全息记录中记录与固定阶段空间电荷场的矢量解析解。在综合考虑空间电荷场的各向异性以及晶体有效电光系数的各向异性后,给出了双中心全息记录的优化记录方向。结果表明,对(Fe,Mn)∶LiNbO3晶体633nm寻常光记录,优化记录方向主要由有效电光系数决定,光栅波矢与光轴夹角为22°,方位角为30°;对(Fe,Mn)∶LiNbO3晶体633nm非寻常光记录,优化记录方向主要由固定空间电荷场决定,光栅波矢与光轴夹角为44°,方位角为90°。

Vectorial Analyses and Recording Direction Optimization in Two-Center Holographic Recording

Vectorial analysis is done for Kukhtarev equations describing the nonvolatile holographic recording in doubly doped crystals, and the bulk photovoltaic effect and external electrical field are considered. On the basis of small signal approximation, the vectorial analytic solutions to the space-charge field for two-center holographic recording in the recording and readout phases are deduced. Considering the anisotropy of the space-charge field and effective electro-optic coefficient, an optimal recording direction of the two-center holographic recording is given. The optimal recording direction is determined mainly by the effective electro-optic coefficient, in (Fe, Mn):LiNbO3 crystal recording with 633 nm ordinary polarization beams, and the grating vector has a 22° angle to the optical axis and a 30° azimuth angle to x axis. But the optimal recording direction is determined mainly by the fixed space-charge field, in (Fe, Mn):LiNbO3 crystals recording with 633 nm extraordinary polarization beams, and the grating vector has a 44° angle to the optical axis and a 90° azimuth angle to x axis.