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基于严格的电磁场理论应用有限差分法研究了栅格表面的光散射和吸收的理论，并计算了具有任意截面形状的一维栅格在平面散射及锥形散射情况下的光声角共振曲线．文中引入了依赖于两个形状参数的准正弦形模型来模拟实验条件下的栅格截面．针对实验条件用ｐ偏振或ｓ偏振的入射光，通过选择合适的形状参数，计算光声角谱曲线的结果和实验符合得非常满意．计算稳定可靠．因此，当栅格材料的物理参量（如介电常数等）已知的情况下，通过理论计算和实验曲线的拟合，可以估计栅状表面的几何参数（高度和周期）和表面形状．
Based on the strict theory of electromagnetic field, the theory of light scattering and absorption of grid surface is studied by finite difference method. The photoacoustic resonance curve of one-dimensional grid with arbitrary cross-section under plane scattering and cone scattering is calculated. In this paper, a quasi-sinusoidal model that depends on two shape parameters is introduced to simulate the cross-section of the grid under experimental conditions. According to the experimental conditions, using the p-polarized or s-polarized incident light, the results of calculating the photoacoustic angle spectrum by selecting the appropriate shape parameters are in good agreement with the experiment. Calculation is stable and reliable. Therefore, when the physical parameters (such as dielectric constant) of the grid material are known, the geometric parameters (height and period) and the surface shape of the grid-like surface can be estimated by fitting the theoretical calculation and the experimental curve.