Fluctuation correlation of the scattered intensity from two-dimensional rough surfaces.

The fourth-order moment of the scattered light, namely, the correlation function of the scattered intensity fluctuation from two-dimensional optically weak homogeneous and isotropic rough surfaces obeying Gaussian distribution are investigated based on Beckmann theory and Gaussian moment theorem. Analytical and numerical results are given for the correlation functions of the scattered intensity fluctuation. Also two important special cases, two-frequency correlation and angular correlation, are discussed, as well as the influence of the incident and observation conditions and the characteristic parameters of the rough surfaces on the correlation function which could lead to a more clear understanding of the scattering property of the rough surface and provide a theoretical basis for the 3D target recognition.