采用折射率调制特性为上凸型和下凹型的调制曲线,提出了线性化求解非线性记录全息图耦合波方程的方法。以反射相位型全息光栅为例,用耦合波理论分析计算了记录介质折射率调制为上凸型和下凹型调制曲线的体全息图的衍射光谱特性。计算结果表明, 折射率调制类型对光栅衍射光谱的带宽有较大影响,对次峰峰值也有影响,而对主峰峰值和峰值位置影响不大。这些结果可以解释实验测得的全息光栅衍射光谱带宽较宽和光栅衍射光谱的多样性。

To solve the coupled wave function of nonlinear recording hologram, the linearization method was advanced, and two modulating models of refractive index were adopted, the convex curve and the concave curve. Taking the reflective phase hologram grating as an example, the spectral properties of the gratings were analyzed, for recording material with refractivity modulated in the convex curve and concave curve, by the coupled-wave theory. There is great influence on the bandwidth of the spectral properties from different modulating models of refractive index, and it affects the secondary peak value, but the primary peak value and position. The results can explain the diversity of spectral property and the experimental bandwidth wider than that calculated.