粗糙介质面对光波束的散射理论

研究当入射场为波束时的粗糙介质质面的散射问题，利用波束的平均波谱展开方法及其尔霍夫近似理论导出垂直极化的散射场和非相干截面计算公式。结果表明，当入射波束照射在粗糙面的区域近似为均匀照射以及波束照射的粗糙面的线性尺寸大于粗糙面度度起伏的相关长度时，非相干后向散射结果与平面波照射时的结果完全相同；当介质本征阻抗趋于零时，非相干后散结果与全波法得到的理想导体的非相干截面结果趋于一致。

Research on the scattering of an incident Gaussian beam by a rough dielectric surface

The problem of the scattering of a Gaussian beam by a rough dielectric surface is studied. By using the plane wave spectrum expansion and Kirchhoff approximation theory, we derive the formulas for the scattered field and the incoherent scattering cross section for Gaussian beam illumination of a rough surface. It is shown that provided the incident Gaussian beam illumination is approximately homogenous over the extent of the rough surface patch and linear dimensions of the rough patch are large compared with the surface height correlation length, the incoherent scattering cross section is the same as for an incident plane wave, and when intrinsic is set equal to zero, the incoherent scattering cross section given in this paper agrees with the result for the case of the perfectly conducting rough surface with illumination of the Gaussian beam.