Numerical Analysis And Experimental Investigation Of Characteristics Of Polarization Scattering Light From Random Rough Surfaces Under Near Infrared Incident Light

Scattering from random rough surfaces is of great significance in laser target detection and precision guiding. This PhD thesis mainly focuses on the characteristics of scattering light from random weak rough surfaces when the incident wave owns the wavelength of905microns. Based on the simulation of scattering light from metal and dielectric surfaces, the mechanisms of the scattering have been discussed and explained. The simulation results were also verified by experiments.Considering randomness of rough surface, this PhD thesis has established the Monte-Carlo method based on the Kirchhoff approximation. Local field of each point on rough surface could be solved according to Kirchhoff approximation. Substituting Local field into classical electromagnetic scattering integral equation (Stratton-Chu equation) and making equation applicable in numerical simulation, the scattering light polarization properties could be studied. Since these process applies to vectors, both strength and direction of scattering light could be analyzed.In order to achieve high efficiency simulation, based on one-dimensional approximation, This PhD thesis has numerically calculated scattering light characteristics from random rough surfaces with different statistical parameters. Covering the weak rough range, this study has clearly shown the scattered light intensity distribution at different conditions (standard deviation, correlation length, incident polarization, surface material, etc.). By analyzing the main mechanism of scattering, it shows that characteristics of scattering light are induced by probability distributions and reflectivity of local area.In this PhD thesis, the numerical simulation on hemispheric distribution of Stokes parameters has been realized. Studying on Stokes parameters of scattering light from metal and dielectric rough surfaces, the V vector distribution of metal scattering light owns peak, while that of dielectric scattering light is around zero. Since the distribution characteristics of the V component has been attributed to the phase difference induced by refractive index, slope distribution and reflectivity of local area, the V component detection could be applied to distinguish different materials such as metals and dielectrics. Since it is difficult to measure Stokes parameters hemisphere distribution of scattering light, two representative curves have been selected to verify the numerical simulation. Experiments have been designed to measure the scattering light in and out of the incident plane on the rough surfaces of metal and dielectric. The experimental data have reflected the main features of the simulation results, in particular, shown the different Ⅴ component distribution of metal and dielectric surfaces. Experimental results fit well with numerical simulation which shows by applying characteristics of Ⅴ component distribution scattering light, different materials such as metals and dielectrics could be determined.