给出了利用角度复用技术同时存储两幅光栅于光折变记录介质同一空间点上的稳态空间电荷场解析表达式。发现第一幅光栅的基频分量中含有第二幅光栅的二阶分量的交扰,而其二阶分量中却含有第二幅光栅的基频分量的交扰。发现空间电荷场基频分量、二阶分量随归一化的光栅波矢(k/k0)变化的最大值偏离了单幅存储时的最大值,以及第二幅光栅的自身变化对第一幅光栅的二阶分量的交扰影响远大于其对第一幅光栅的基频分量的交扰影响。同时还发现了调制度m只影响空间电荷场的振幅,并不影响空间电荷场随k/k0变化的极值点位置。

With two pieces of phase gratings stored in one point of photorefractive materials, the analytic expressions for the first two higher-order harmonics of the stationary space-charge field are presented by using “the hopping model” of Feinberg. The results indicate that the fundamental and second harmonic of the space-charge field of one of grating are coupled with the second and fundamental harmonic of the other grating, respectively. The positions of the maximum values of the normalized fundamental and second harmonic of the space-charge field versus the normalized grating vector (k/k0) in two pieces of grating are deviated from that in single piece of grating. At the same time, it is found that the degree of deviation of the spatial second harmonic of the space-charge field more strongly depends on the difference of normalized grating vector (k/k0) of the two pieces of gratings than that of fundamental harmonic. Besides, the degrees of deviation for both harmonics do not depend on the modulation depths.