Difference Scattering Field Properties between Multilayered Defect Particles and Slightly Rough Optical Surface

Based on half-space finite difference time domain and Monte-Carlo method, composite scattering between rough optical surface and defects is investigated numerically. The defects are observed as multilayered particles for a more complex situation. In order to obtain the scattering contribution of defects, difference radar cross section is added into the calculation model of the proposed method. Selected calculations on the scattering contribution of multilayered particles or rough optical surface are analyzed in detail to demonstrate the best position to find the multilayered defects inside the optical surface is to detect in steps of a fixed degree for the incident angle.